Apr 2005 a friend and I built up a nice 402 big block and dropped it in my Chevelle. The engine runs good and strong and doesn't even have 500 miles on it yet.

Sometime in 2006 I picked up a 400 sbc, 330817 casting, I sold all of the internals and heads and had the block itself checked by machine shop. Block checked good, and I had intentions of using it in another project, but said project is now sold. :(

I want to set my car up for some strip action. Seems like everyone I've talked to has said a 396 or 402 big block doesn't run any better than what a 355 or even a 383 small block can run at the track.

With that said I've kind of wondered if I oughta pull/sell my 402 big block and just build up a 400 small block instead? Perhaps I'll shed 100 + lbs off the nose?

I like the big block myself I ran mine on the stret and strip for years and enjoyed it. 396+.060 ISKY 292/.590 cam TH400/3200 stall 4:56 12 bolt. I would keep the big block myself but thats just me. If I was going to step up it would be to a bigger big block. Sell the 400sb and find a 454 shortblock, swap the top end from the 402 over to the 454 and have a blast.

I would stash the 400 sb away, sell the 396 as a shortblock and find a 454. You already have all the little things like brackets,pulleys, waterpump etc and are setup. People use to think my 350 was a 396 when they went for rides until I popped the hood.

I would keep the 402 in it and use it until you have the drivetrain and chassis worked out. Why pull it with 500 miles on it?
Spend the money on suspension, tranny/converter, tires, gauges, fuel system, NOS, etc. etc.
Stuff you can use regardless of what is under the hood - a lot more to a race car than just the engine.
Then build a new engine in your spare time while you are racing with what you have already.

I agree on running what you have. For a car that's never been down the track before, it doesn't matter how much power the car has if the rest of the car isn't sorted out .

396/402 is fine.
What are your ET goals?

500 miles does'nt seem like your giving it a chance. if ya gotta have more then i'd source a 454 to build. you can build a strong 400 too,but when you get around the 500hp level the 454 will be a more streetable motor, and cheaper to build. you can probably make up to 550 hp and lots more tq with the bbc top end on your 402 now using a flat tappet cam and a stock 454 bottom end. the 400 will require a good rotating assembly and good aftermarket heads and probably a roller cam to top 500hp. if you decide to go the 454 route keep your 402 as a backup.

396/402 is fine.
What are your ET goals?

x2

I'd take a 396/402 over a 400sb anytime:thumbsup:

Thanks for the input.

My goal is to get my Chevelle (3800 lbs w/me in it) into the 11's. W/O the help of spray.

I had considered a 454 shortblock like someone mentioned but there's a few things to know...

1. The engine I have is an L34 396, which is a correct engine for a '70 Chevelle SS, and the heads match it too, so I kinda thought that if I were to sell the engine the heads should go with it...I figure it's worth more and especially to someone needing a date correct engine for their 70 Chevelle.

2. The heads are the 290 oval ports still fitted with 2.06/1.72 valves....won't that "choke" the air flow/performance of a 454? I know I could mod them for bigger valves but then wouldn't that interfere with the 402 and valve shrouding?

Now as for building the 400, I figure I will essentially have the same thing minus 100 lbs or so weight on the nose.

Perhaps I'd be better off building a fairly mild 454 and using the 290 oval port heads as they are? Could I still make 500 hp with a set of fairly stock 290 oval port heads?

I would keep the 402 in it and use it until you have the drivetrain and chassis worked out. Why pull it with 500 miles on it?
Spend the money on suspension, tranny/converter, tires, gauges, fuel system, NOS, etc. etc.
Stuff you can use regardless of what is under the hood - a lot more to a race car than just the engine.
Then build a new engine in your spare time while you are racing with what you have already.


Excellent advice! I agree completely, FWIW.:D


Randy

Put in a high 240ish/low 250ish @ .050 solid lifter cam,(leave the rest of the motor alone other than correct valve springs) and a 4000 flash stall and let us know how you do :D

Good advice here.....
Keep the fresh 402. You never stated your intake and cam, what converter, what gears, what chassis is prep and what tires you run...at least on this thread. It's all about the combo.
For example:
One of my smarter friends has his beautiful silver SS 396 350 horse 4-spd.
I went for a ride, it was nice....just didn't inspire me. His track times were slower than my 350-powered 70 Elky.... Turns out he had 3.31s but mated to a 2.20 geared M-21....small wonder it was a dog launching. He's since upgraded to a TKO 600RR gearbox..... and if you have the right parts, you gotta rev the piss on a 396, 6500 rpm, not 5000 as my pal was doing. I think FRYNTYR taking him out in his 427 69 Chevelle this weekend demonstrated the RPM capability of short stroke BBCs. The 396 is sensitive to gearing and combination, 454 with the extra inches is a more forgiving platform.

No sense changing the BBC out, too much hastle to go to SBC 400 for the headers and other accessories...money better spent on your Chevelle's chassis/traction goodies. And as the guys said, 400s need good heads, rotating assy, etc. Far cheaper to stay in the BBC family. My $.02.

You never stated your intake and cam, what converter, what gears, what chassis is prep and what tires you run...at least on this thread. It's all about the combo.


Oops...you're right

Edelbrock Performer RPM intake
Comp Cam 240/246 duration @ .050, .574/.578 lift cam with 1.7 rockers
Hughes 3000 stall converter
TH350 trans, 2.52/1.52/1.00 gears
4.10 ring and pinion gear in 12 bolt housing, posi trac
UMI performance tubular lower control arms, stock uppers (I do have UMI adjustable tubulars for the top
Stock shocks, stock coils

I have a set of 275/60/R15 M/T ET street drag radials to run

JD - bolt the M/Ts on and run it this weekend!!:yes:
What are you waiting for?

I am jealous - no way I will have my '64 done before the snow flies.:(

I would take out the 4.10 and put in a 4.56 and youd be suprised! maybe a little higher on the stall. Like everyone else said you have to do some chassis tuning also its not all in the engine. 700 cubic inches wouldnt be any good if you cant put it to the ground.

sounds like you should give the 402 a chance.

JD - bolt the M/Ts on and run it this weekend!!:yes:
What are you waiting for?


1. I don't have the ET street drag radials mounted.....yet. I have a set of 15X8 rims to mount them on, still need to do that. Hopefully a 3 inch back space is ok.

2. I am somewhat worried my 12 bolt will break an axle while launching....despite having an auto with no transbrake. My rear doesn't have any "leaky" c clip eliminators on it....not sure how well it will hold up w/o breaking something....

3. I still have the stock upper control arms, not sure how well they'll work, guess i can always try it and see....?

4. I need to get myself a copy of the 2007 IHRA rulebook so the track officials don't kick me out the first time I come in...

I think you'll be fine. I know my friend has 30 spline axles in his rear and it goes 11.70's and 1.58 in 60' with a trans brake. Vinny on this board has 30 spline axles and has gone 10.30's and 1.40's in 60'. My car went 10.70's with the stock upper and lower control arms in it. Getting the rule book is always a good idea to see if there is anything you've missed.

1. I don't have the ET street drag radials mounted.....yet. I have a set of 15X8 rims to mount them on, still need to do that. Hopefully a 3 inch back space is ok. (ANSWER-all you can do is mount the tires and see if they fit)

2. I am somewhat worried my 12 bolt will break an axle while launching....despite having an auto with no transbrake. My rear doesn't have any "leaky" c clip eliminators on it....not sure how well it will hold up w/o breaking something.... (ANSWER-My 12 bolt doesn't have c clips eliminators and I have been racing my 70 SS454 2-3 times ayear for the last 6 years...and I drive it 270 miles round trip)

3. I still have the stock upper control arms, not sure how well they'll work, guess i can always try it and see....? (ANSWER-they will work fine. I run a completely stock rear suspension on my 70 SS)

4. I need to get myself a copy of the 2007 IHRA rulebook so the track officials don't kick me out the first time I come in..(ANSWER-I have never owned one and don't need it..plenty of info on line)

Stop making excuses and go find out what your car runs! :thumbsup:

Stop making excuses and go find out what your car runs! :thumbsup:
X2,3 &4!:D

2. I am somewhat worried my 12 bolt will break an axle while launching....despite having an auto with no transbrake. My rear doesn't have any "leaky" c clip eliminators on it....not sure how well it will hold up w/o breaking something.... (ANSWER-My 12 bolt doesn't have c clips and I have been racing my 70 SS454 2-3 times ayear for the last 6 years...and I drive it 270 miles round trip)


Ok, your rear doesn't have c clips, mine still does. That's what I was inquiring about. ;)

I ran my old Nova till it went 11.50's with C clips.
your not making enough HP to worry about them.

Ok, your rear doesn't have c clips, mine still does. That's what I was inquiring about. ;)
i think Chris meant he doesn't have C clip eliminators

I think 11's with a 402 will require a pretty serious setup....high rpm.
With a 468....much easier and can be done with 3.55 gears.

The 290 heads are fine for a 454 with bowl work and the stock valve sizes. If I'm not mistaken, the 290 is a semi open chamber head and 107cc.

I had a full weight 70SS with 468, flat tops, 290 heads, Comp 280H, Perf RPM, 750 Holley, 2" Hookers and 3" exh that went a best of 11.92 @ 113. (At sea level)

3.55 gears, stock 12 bolt posi, 10x29" slicks.

Very fun and consistent car! I did well in the brackets with it and always drove it to and from the track.
I took the engine and trans out and sold the car for $2000 in 1996....wish I still had it!

BTW.....I've had C-clip eliminators in the Nova for 10 years now and they don't leak.

Ron

As long as the outer seals are O.K., no rear end should leak. There isn't much fluid out there to leak. The thirty spline axles aren't the weakest part of the 12 bolt style rear end anyhow. The first thing that breaks are the spider gears in the posi-trac unit, then next most likely would be the ring and pinion gear's teeth. The studs that hold on the wheels would be the next most likely, but that rarely happens. Any driveline failure usually happens right at the starting line.

i think Chris meant he doesn't have C clip eliminators

yes..that is correct. My error.
I still do have c-clips

Stop making excuses and get some timeslips :) its a blast making a 1/4 mile pass

Stop making excuses and get some timeslips :) its a blast making a 1/4 mile pass


QFT. Do a saftey check on all your components, full the tank about 3/4, make sure the lugnuts are tight and nothing is leaking and roll out!!

Thanx, I finally ran the car this weekend, very poor results, ran with the MT ET street drag radials, out of 5 runs my best 60 ft. was a 1.87 and the worst a 1.91 and thats with the tires at 15 PSI.

I won't even post the e.t. or the trap speed as the engine decided to nose over at 5k which yielded bad results...I'll only say it ran a piss poor disappointing run all five times.

If it were a hose I would've shot it by now.

Another vote for the BB...set up your chassis and do all you can with it. I've seen a 307/3 spd 71 Camaro run low 13s due to constant tweaking, getting everything dialed in just right. That 402 should be making tons of torque. Best thing you can do is make use of it. Yeah, you could lose some weight with a sb. You could also spend a similar amount that you would have to build that 400 on a good set of aluminum heads and lose nearly that much weight.

Devin

Thanx, I finally ran the car this weekend, very poor results, ran with the MT ET street drag radials, out of 5 runs my best 60 ft. was a 1.87 and the worst a 1.91 and thats with the tires at 15 PSI.

I won't even post the e.t. or the trap speed as the engine decided to nose over at 5k which yielded bad results...I'll only say it ran a piss poor disappointing run all five times.

If it were a hose I would've shot it by now.
i know it's a PITA, but have you dropped the tank to make sure the picj up/sock isn't full of crap (rust and debris)? do you have the recommended springs installed at the recommended hieght? the more info you can give on 60ft, trap speed and ET even your 330' time and 660' times and mphs if available, the better advice you can get. was the 60ft off because you were spinning?

If you have the disease, save your dough and just buy a big displacement motor when you have the coin. It will save you a ton of $ in the long haul.
Enjoy what you have and upgrade to prepare your car for more power some day just as 64cdnss suggested.
That motor you have is no slouch, have fun,
just my 2 cents.

Thanx, I finally ran the car this weekend, very poor results, ran with the MT ET street drag radials, out of 5 runs my best 60 ft. was a 1.87 and the worst a 1.91 and thats with the tires at 15 PSI.

I won't even post the e.t. or the trap speed as the engine decided to nose over at 5k which yielded bad results...I'll only say it ran a piss poor disappointing run all five times.

If it were a hose I would've shot it by now.

Please post your times..we are here to help.
Again,as I mentioned in your other thread posting the incrementals can only help solve the problem.
1.87-1.91 60 ft. ain't bad either...

It ran a 13.42 at 98 mph. I know, very disappointing, even a modest 350 could do that right...?

It has alot of off line torque and a fairly good mid range too, but top end it flat out sucks.

I asked one spectator that I knew if he saw me spinning or wheel hopping. He said it looked like a smooth shot off the line.

For a mild cammed smaller cubed BB, that's not bad. :thumbsup: A stock LS6 Chevelle ran about the same.
What were you expecting???

What was the 1/8 mile ET/MPH?

Don't knock it,13's with your fuel issue is nothing to be bummed out about.
Heck,my current combo went a 14.50 first time out way back when I had manifolds on it,no tuning and street tires. Went back and ran a 13.74 with the manifolds and drag radials.
Fix that fuel issue and you' be golden.

For a mild cammed smaller cubed BB, that's not bad. :thumbsup: A stock LS6 Chevelle ran about the same.
What were you expecting???

Thanx Bill. As the car sits right now I was expecting somewhere in the upper 12's. You know, a 12.8, 12.7....something like that.

What was the 1/8 mile ET/MPH?


Below is the best time slip I got...

60 ft: 1.8759
330 ft: 5.4339
1/8 ET: 8.4795
1/8 MPH: 80.26
1/4 ET: 13.4201
1/4 MPH: 98.36

Sorry the time slips I have do not show me a 660 time, only a 330 time.

1/8 mile is the 660' time. And like was said before, don't get discouraged. You are not far off of where you want to be and it doesn't take much to set you back. I've said this before but my first weekend I took my car out after 3 years of building I thought I had all the bases covered. The wrong U-joint on the driveshaft caused a wicked vibration that cracked the case on the trans and the valve springs floated at 7000 rpm. It went 11.79. One joint, case and new springs and it went 11.27 next time out.

Below is the best time slip I got...

60 ft: 1.8759
330 ft: 5.4339
1/8 ET: 8.4795
1/8 MPH: 80.26
1/4 ET: 13.4201
1/4 MPH: 98.36

Not bad at all, Dawg! Don't be discouraged.
I bet 80% of the BB Chevelles I see every year during the CB drags in Nashville run pretty darn close to those numbers.
And will only get better with some tuning...

You are not picking up 20 MPH on the big end
80.26 vs. 98.36
MPH should be around 100-101 so you have fuel/jetting issue for sure.
Actually,with the cam you have I would like to see 85 MPH at the 1/8 and 105-106 at the 1/4 when tuned and dialed in.

As Bill said,don't be discouraged. Mid 13's is pretty respectable and you have alot more in it.

If it helps any I have #82 jets in the rear.

Also someone told me I should replace the Holley chrome dual feed line and in it's place run two 6 AN braided lines off the regulator to the carb.

I have also been told that perhaps I need to run jet extensions in the rear so the jets are covered with fuel. :confused:

No 13.4 isn't bad but not that good by my standards, especially when there's LS1 Camaros and 4.6 Mustangs running 12's at the track. :(

If it helps any I have #82 jets in the rear.

Also someone told me I should replace the Holley chrome dual feed line and in it's place run two 6 AN braided lines off the regulator to the carb.

I have also been told that perhaps I need to run jet extensions in the rear so the jets are covered with fuel. :confused:

82's in the rear should be fine..FYI I run 83's or 84's

You do not need two 6An braided lines.The Holley line works fine on both my 750 v/s and 750 d/p to run mid 12's

I do not have jet extensions on any of my carbs.

I think you have a dirty sock in your gas tank
Are the stone filters removed from the inlets on your Holley?

Is the car originally a SB car...possibly have 5/16" fuel line??

Dawg, your car definately has more left in it once you get the fuel problem resolved. for your first time at the track that's not bad. i knew you were expecting a little too much from your posts over on Maliburacing. i would say once you get the bugs worked out and tuned in real good you will see mid 12's. judging by the 1/8mi vs 1/4mi time it seems that you are definately having fuel delivery issues. something must be obstructing the fuel from reaching the carb in one way or other. it seems like it really doesn't affect it until the second 1/8mi somewhere, because your 60ft, 1/8mi ET, and 1/8mi mph seem to jive pretty well, it's the 1/4mi mph that tells me something is holding it up. you should probably be picking up at least 20mph probably more like 22mph on the back half of the 1/4mi, imo. what does your convertor flash to when you launch it? you may need a looser convertor at some point, but i'd get the fuel issue whipped first. the dragstrip can be a VERY humbling place, i've been there too.

JunkyardDAWG
You are doin' great!
My good pal was running 15s at 90 something until he went to the TKO and street radials this weekend for his 69 SS.....mild 350 horse 396 with small cam, stock 4v intake and Q-jet.....headers....3.31s, he ran 14.3 at 99.

So you into the 13.4s with 98 mph....you are really in the hunt already.
I'd have expected more mph too with your pretty darn good 60' time.

If you are really unhappy with your 396, I'll come out to Fayettenam and trade you the mild 350 right outa my 70 Elky for it! With tired suspension and street tires, I pulled an earth-shattering string of 15.28/.27/.26 at 89.8/89.9 and 90.0 mph. I was happy because I expected realistic goals of 14.99 OR 90mph for my first outing. Next time I expect to whittle a few tenths off the times and coax another 1-2 mph outa her.....

You have EVERYTHING to be happy about....get that engine some fuel and let her rip!

I think you have a dirty sock in your gas tank
Are the stone filters removed from the inlets on your Holley?

If the sock was dirty....well i dunno how it got that way. :confused:

I had the tank vatted a year ago to get 36 years worth of crud out of the tank. I also then installed a new sending unit with filter.

I guess I could drop the tank again and see what's going on. Or install a fuel cell with an 8AN line all the way up to the fuel pressure regulator. :)

Oh, and yes I removed the "stone filters' off my Holley.

Is the car originally a SB car...possibly have 5/16" fuel line??

It was an original sbc car....350 sbc to be exact...but I measured the line and it looks to be a 3/8.

what does your convertor flash to when you launch it? you may need a looser convertor at some point, but i'd get the fuel issue whipped first.

Not real sure, it's a Hughes 3000 converter, I really didn't pay much attention to it at the track other than when it was hitting close to 5k...while staging I kept my eye on the tree as my biggest thing was getting good lights and working on my launching.

The cam duration is 240/246. The cam lift with a 1.7 rocker is .574/.578. I think people told me at first I'd need a 3500 stall but I already had a 3000 so that's what I used.

Nothing wrong with that time,I ran 13.42 (@ 107 I think?) first time out in my 402 also,weird huh?Just keep working with what you have before you start changing parts/engines.There's a ton of e.t. to be found just by tuning.Enjoy the car for awhile.

If you have a fuel issue,and if the sock and pick up is fine,I wonder if it could be the pump?

Good job JD! You will be in the 12's in no time!

Thanks....

I guess it could be the pump, it is a relatively new pump....

What kind of pump and regulator? How much fuel was in the tank? Was it breaking up or just flattening out? Does this all happen after the 1/8 mile? What kind of valvesprings are with that camshaft? Were you launching from idle or did you footbrake it up there a bit?

For reference, Chevelles like to uncover the pickup tube when the fuel is half full or less in a hard running car, but normally it's between launch and 660' (for me anyway) and sucks air. Your first time results arent bad at all, but im surprised a lot of people expect their car to run 11's first time out. Must be all the BS the magazines spew these days. You'll get into the high 12's no problem...that cam is big enough to do so.

Happy tuning!!!

The jet extensions aren't going to help. If your car was leaving and stumbling then they would help. Down track is another issue.

What kind of pump and regulator? How much fuel was in the tank? Was it breaking up or just flattening out? Does this all happen after the 1/8 mile? What kind of valvesprings are with that camshaft? Were you launching from idle or did you footbrake it up there a bit?


Holley 130 gph mechanical pump
Holley 12-803 regulator
It seemed like it was both breaking up and flattening out
It happens anytime I run over 5000, doesn't matter what gear I'm in
Guy said the springs were L88 style, I bought the heads assembled so i know nothing on how they're set up, was told they're good up to .600 lift
I launched both from idle and holding the brake. Same results each time.

It happens anytime I run over 5000, doesn't matter what gear I'm in

What distributor? HEI? If so, a stock module? ;)

Highly doubt it's a fuel pump/fuel delivery issue. I've ran my 454 motor to 6000 (prior to valve float setting in) with no real signs of flattening out using nothing more than a 120GPH mechanical pump. Never checked the fuel pressure at WOT, we'll do that once I get the valve train straightened,get the 3" exhaust on it - and run it on the dyno.

I tend to agree, would look into the ignition and also double check the valvetrain.

What distributor? HEI? If so, a stock module? ;)

Mallory HEI, not sure about the module, I don't think it's a stock GM piece...

396/402 is fine.
What are your ET goals?

x3

What carb are you running?

Holley 750 part number 82750

Holley 750 part number 82750

is it a vacuum secondary?

Dawg,

How streetable is your car with the rear and the 3000 stall,

I was thinking of going to a 3.90 from a 3.31 and my stall is a 2500

car is very streetable now but a little light down low, torque wise I have a .232 and .242 @.50 and 575 595 lift cam ,
hydro roller, roller rockers, holley 3310 and c396 edelbrock intake


I would be happy with you times by the way , I would love to see that at the track but I have not gone yet

is it a vacuum secondary?

Yes.

Just to help you all out here's the carb I have:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D0%2D82750&N=700+0&autoview=sku

And this is the fuel pump I have:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D12%2D454%2D13&N=700+0&autoview=sku

This is the ignition system I run:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=MAA%2D8548201C&N=700+115&autoview=sku

-And-

http://store.summitracing.com/partdetail.asp?autofilter=1&part=TAY%2D74003&N=700+4294864973+4294908216+4294925080+4294908021+ 4294840133+4294786310+4294791717+4294864966+115&autoview=sku

And here's a break down of what's inside the ignition:

Module:
http://store.summitracing.com/partdetail.asp?part=MAA-607

Coil:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=MAA%2D29212&N=700+4294890813+115&autoview=sku


And heres the fuel pressure regulator I have: http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D12%2D803&N=700+0&autoview=sku

And this was the dual feed fuel line that I've been told to ditch in the trash because it doesn't feed the rear bowls like they need to be fed:
http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY%2D34%2D150&N=700+0&autoview=sku

Which by the way I did discover when I removed the dual feed line the inlets on that bowl were dry....the fronts were wet.

Dawg,

How streetable is your car with the rear and the 3000 stall,

I was thinking of going to a 3.90 from a 3.31 and my stall is a 2500



Mines ok, the 3000 stall has alot of slip IMO so cruising at 40 it seems like the rpms are only around 2000 or so unless I mash the pedal, then it tells me different.

On the interstates it's totally different, it usually sings at or above 3000 most of the time.

Junkyard,I'm willing to bet your secondaries aren't fully opening due to a too stiff secondary spring..try the shortest yellow spring that comes with the spring kit.This the quickest opening spring that Holley makes.
It might be as simple as that.Its like not having full throttle. On a vacuum carb,the linkage control only the primaries and that spring does the rest.Too tight,no WOT

If you all ready have that spring in there,proceed as planned with the other items to check.

Mr 4 speed I will try that. I will tell you now the spring that's in my carb is the same one that was in it when I bought the carb new.

Also I don't know if this is of any help or not but....

I just took off the old dual feed line, and it didn't seem like there was any wetness inside the carb on the rear side where the gas lines connect.

I eneded up running dual 6 AN lines to the carb and started it up. Damn engine ran pig rich like you wouldn't believe. Cracked both of the sight screws and the rear was pouring out while the front was level with the sight hole.

Took the bowl off and cleaned out the float, noticed alot of sandy goldish looking deposits come out, perhaps it was from the "stone filters"?

Put it all back together, fired it up, ran much better now, I've yet to take it out and run it wide ass open throttle to see if there's any difference, will probably do that tomorrow.

Sounds like you might have found your issue. Go back to the track ASAP :)

thanks for the info on the streetablilty,
give me food for thought.............mmmmmmmmmm food:D

Sounds like you might have found your issue. Go back to the track ASAP :)

Not quite....

I put in the shortest yellow spring in the secondary like you said to do...

I didn't take it to the track but I did do a few trial runs out on a back country road....

It's still doing the same thing....sputtering...

This time I found it';s doing it around the 5300-5400 mark, and the fuel pressure is at 5.5 PSI. It doesn't seem to change at all when I run it high either.

Not quite....

I put in the shortest yellow spring in the secondary like you said to do...

I didn't take it to the track but I did do a few trial runs out on a back country road....

It's still doing the same thing....sputtering...

This time I found it';s doing it around the 5300-5400 mark, and the fuel pressure is at 5.5 PSI. It doesn't seem to change at all when I run it high either.
do you have a rev limiter or 2 step ignition? will it not go past 5300-5400rpms or does it just miss out after that point?
it's not something silly like breaking in the cam without the inner springs and you forgot to reinstall the inners, right? i was just thinking since someone else put it together maybe he didn't install the inners so you could break the cam in and forgot to tell you to put them back on after break in? it sounds like maybe valve float or an ignition problem. it does it at the same rpm in every gear, right?

I wonder if you have the right valve springs.. I would think with that cam you would get more mph and a little more rpm. I know it might be a PITA but you might want to remove a couple of springs and get them measured.

do you have a rev limiter or 2 step ignition? will it not go past 5300-5400rpms or does it just miss out after that point?
it's not something silly like breaking in the cam without the inner springs and you forgot to reinstall the inners, right? i was just thinking since someone else put it together maybe he didn't install the inners so you could break the cam in and forgot to tell you to put them back on after break in? it sounds like maybe valve float or an ignition problem. it does it at the same rpm in every gear, right?

No I do not have any type of rev limiter or 2 step, just a plain Mallory HEI.

When it hits 5300 it (to me) feels it stops pulling and starts sputtering.

As mentioned I bought the heads already assembled. If memory serves me correctly I believe I saw both the inner and outer springs on there.

Yes this happens in any gear, all at the same rpm.

I wonder if you have the right valve springs.. I would think with that cam you would get more mph and a little more rpm. I know it might be a PITA but you might want to remove a couple of springs and get them measured.

Yeah I'm beginning to also believe I've got valve float. Fortunately I happen to have the correct valve springs/retainers/locks sitting in the box in the bench to do the swap if I wanted to/needed to....

But to swap them looks like I'll need to pull the heads....which from what I've gathered is so much of a PITA, that I may as well pull the whole engine....which I've had in and out twice now, and probably will not reinstall if I do end up pulling it...anyone want to buy a built 1970 Chevelle SS 396 engine with less than 500 miles on it?

You can change the springs on the engine without too much difficulty. Assuming you have a compressor, put air to the cylinder you want to change the springs on. This will keep the valves closed. There are tools that are readily available to change them from there. Not a big deal to do.

Devin

No I don't have a compressor, but I can get one.

The big thing is I don't know how to set up valve springs on heads, so that's something I'll need farmed out unless someone wants to come over and visually show me how to do it, then i can figure it out.

No I don't have a compressor, but I can get one.

The big thing is I don't know how to set up valve springs on heads, so that's something I'll need farmed out unless someone wants to come over and visually show me how to do it, then i can figure it out.yeah, you'll probably need to take the heads off and take them to a shop, unless you can get somebody to come over that knows how to do it. there's definately alot more to it than just airing up a cylinder to hold the valve and change the springs. you'll likely need some shims and a tool to measure spring height and another to measure spring pressure at recommended height. most people don't have those tools unless they are a fairly serious racer or they build alot of engines.

Did you buy those heads off ebay? Most of those "good deal" units have jsut some cheap valve and spring setup in them for profit. Even though the spring has the lift capability, it does not have the pressure requirements. A hyd cam of that size in a BBC with a heavy valve and so on would like at LEAST 135 lbs on the seat. You can just easily swap in springs without hassle or taking the engine apart... but if you want, buy a valve spring height mic and see what height you have. Then take the springs down to a shop and see what pressures they are at that measuremnt and also check them at open (installed height minus the lift of your cam.)

No, I did not buy the heads off ebay. I bought them from a neighbor that puts together big blocks all the time and has a stash of them in his garage.

The heads match the block I have. He was going to build the engine I now have to put in one of the few Malibus he has sitting around.

He had the heads done first, then he was going to send the block down to the shop to have it machined so he could build it when I expressed interest, that's when he sold me what he had as it was. The heads were fresh back from the shop when I got ahold of everything.

I asked him, he said they were L88 spring good for .600 lift....which I now know is vague. He also said he has a valve spring compressor to remove the springs but that's it....

I'm guessing really the heads would only need removing if the seats needed machining to accept the new springs? Or with my cam do you think maybe the guides need cut down?