Here are some real dyno numbers from my recent swap to vortech heads. 284 HP and 330 torque at the rear wheels. Here's my combo for those of you that did not follow the previous thread:

355 w/ flat top cast pistons
9.5 to 1
Lunati #10010 Hydraulic Cam- .480 lift, 292 duration and .230 @ .050, single pattern
64 CC Iron Vortech heads milled for high lift and springs upgraded
Edelbrock 1406 600 CFM and Air Gap Manifold
Erson 1.52 Roller Rockers
1 5/8" headers
2 1/2" duals with summit turbos
MSD- distributor and 6A box

HP peaked at 4,800. Wow, that was a surprise. The car pulls good up to 6,000 but the dyno says shift at 5,500. I'll head to the track soon and see what I've gained. I'm guessing 2 to 3 MPH.

Test was performed at Conley Performance in Houston on a Mustang Dyno, air temp of 87 degrees. Mr. Conley recommended going up to 3" exhaust, installing an H-Pipe, and advancing the cam 4 degrees. The exhaust work would help the top end, advancing the cam will help the mushy bottom end this cam exhibits on the street. It really comes on at 3,000 RPM and has great mid-range torque. What do you guys think about his recommendations?

graemlins/thumbsup.gif

Before investing in a new exhaust, what you may want to try is pulling your exhaust off at the track to see if it picks up. Maybe even just the tailpipes. If it picks up, this may indicate the need for larger exhaust. I had a friend who removed just the tails and picked up a bunch at the track. This, to us, meant that it wanted more "breathing room". So, on went bigger pipes. smile.gif

Rod

Just a little :confused: ...
if the engine has "a mushy bottom end" then why the 3" exhaust recommendation?
I would say at that power range and RPM, you're fine with the present 1 5/8" headers & 2 1/2" duals.
BTW...the heads are known as Vortecs. ;)

I ran that cam in a 10:1 355, ported 462 heads, and it was a dog. It slowed the car by at least 3 tenths, compared to a HE272.

Imho, you are over cammed!!

A CC 270 Magnum or an Isky 270 Mega will do you nicely AND pick up a bunch of lowend for you!!

I have Mellings version of that cam in my 9.5 to 1 CR., 406 and it is weak until she is above 2500rpm, then hold on!!

I am also under geared, what with my M-20 and 3.31's and at the time 26.5" tall old-fashioned L/60-14" tire's..

pdq67

with the compression only 9.5 to 1 and the small carb (which would be my guess as to why it doesn't make any power past 4800), i think you could hardly call 284 RWHP doggy. i think a tuned in Holley 3310 would put you around the 300hp mark to the rear wheels.

I can call it doggy, because it will fall on it's face everywhere else besides the peak. That's why his builder is suggesting advancing the cam.

A 600cm carb is right on the money for this motor.

Originally posted by TJC:
I can call it doggy, because it will fall on it's face everywhere else besides the peak. That's why his builder is suggesting advancing the cam.

A 600cm carb is right on the money for this motor. sorry, i totally disagree. i've done back to back runs with an Edlebrock 600 vs. a 3310 Holley on a flat top 355 with the same cam mentioned and it was worth .3 on my car, no other changes. i also don't agree with it being flat on bottomend either, i did high 1.70 60ft times at over 3700lbs. i don't think that's too shabby for a little flat top 355 with s/r heads. :confused:

jeez, now I have to go find my old time slips...

Originally posted by TJC:
jeez, now I have to go find my old time slips... i've done quite abit of carb testing on different combos. with the combo i mentioned the car ran an 8.98 with the 600cfm 1406 carb. swapping to the 3310 netted me a best of an 8.61 but on that particular night the best it did was an 8.67. after wringing all i could out of the 3310 i bolted on a 750dp and it ran a best of an 8.56@81mph with a 1.76 60ft time. the best 60ft time with the 3310 was a 1.79, and the best 60ft with the 1406 was a 1.83. that's not lightning fast by any means, but not too shabby for what it was. i know some AFR 195's and some more tuning on the dp would've gotten at least 3 more tenths, even with that lousy cam. :D

BTW, those are 1/8mi times.

i wouldnt say over cammed, look into a carb and tune it.
my motor was a 355 w/ vortecs w/ light port cleanup. 9.35:1 comp cheapo hyper pistons stock rods and crank UNBALANCED, performer rpm cam, .488/.510 lift 234/244 duration @.050, performer rpm intake, 750 holley with polished venturies and milled choke horn.through 1 5/8 headers w/ 2 1/4 pipes w/flowmaster 3 chambers it made 307 rwhp and 363rwtq. with a 2400 stall it ran a best of 13.12 @103 and with a msd,3500 stall it ran 13.06 @103. on a side note with a 100hp shot it ran 12.31@109

The cam and the carb came with the car so I'm trying to run with what I got. I think there could be improvements made with a better cam to match this combo for sure. The carb swap would probably net more HP but I also don't want to mess with throtle response which is great with the 600. Bottom line is that these VORTEC heads are great!

I expected the A/F ratio to be lean after the head swap but it was right on the money according to the dyno and we did not rejet. We just had to set the idle mixture and it was good to go. One more note, we picked up 3 HP by reinstalling the air filter! First two runs were without filter, last run was with a K&N 3" filter.

Found my notes on the cam swap. ( 16 years ago... )

With HE272 ; 13.47 @ 105 idled at 15" of vac
BM2 ; 13.78 @ 101 idled at 12" of vac.

3600 lb Impala, 4.10 rear, 355, UNPORTED 492 heads, 600 Holley, torquer 2, 3000 converter.

Kinda fun reading those old notes. I recall how pissed I was at the results of that swap. Car went from being animal like, to limp noodle.... One other comment says "Passenger thought we had been rear ended" ( dropping from 3rd to 2nd on a roll )

What's an HE272?

Comp Cams High Energy 272 hydraulic. It's old tech now.

Sorry to nit pick but I'm pretty sure Comp never made a High Energy 272. They have a 256, 260, and the 268 then the Magnums start with the 270 then 280. Cam Dynamics (bought by Crane) had an Energizer series that had/has a 272 in it. Again, sorry to nit pick, I'm kind of a cam fan. smile.gif

You may have lower compression than you think. Cast pistons are usually .020" short and with an un-decked block and a rebuilder head gasket of .041", you are probably closer to 9.2, with a quench of .086". This is really really low for a 292º cam. It wants about 10.75-11:1. This is why it is a dog at low rpm. If the chambers are 62cc, which I understand many vortecs are, then the CR is 9.4, still very very low. I wouldn't put a cam bigger than a 272º in it. DCR with the 292 is 6.9 with a 64cc chamber and 7.1 with a 62cc chamber.

Originally posted by trimless:
Bottom line is that these VORTEC heads are great!graemlins/thumbsup.gif I look forward to the track results!

Originally posted by Rmchevelle:
Sorry to nit pick but I'm pretty sure Comp never made a High Energy 272. They have a 256, 260, and the 268 then the Magnums start with the 270 then 280. Cam Dynamics (bought by Crane) had an Energizer series that had/has a 272 in it. Again, sorry to nit pick, I'm kind of a cam fan. smile.gif Jeez, you're right. It's even in my log book. graemlins/boring.gif

Originally posted by TJC:
Found my notes on the cam swap. ( 16 years ago... )

With HE272 ; 13.47 @ 105 idled at 15" of vac
BM2 ; 13.78 @ 101 idled at 12" of vac.

3600 lb Impala, 4.10 rear, 355, UNPORTED 492 heads, 600 Holley, torquer 2, 3000 converter.

Kinda fun reading those old notes. I recall how pissed I was at the results of that swap. Car went from being animal like, to limp noodle.... One other comment says "Passenger thought we had been rear ended" ( dropping from 3rd to 2nd on a roll ) what were your 60ft and 1/8mi times? you got 12" of vacuum with a torker 2 and that cam on a 355? that is impressive, no way you could have had that cam retarded. i think mine only made around 9 or 10" of vacuum and i had an rpm intake. :confused: i had the same gears and a cheapo Torkmaster 3000 convertor. car weighed 3760lbs with me in it.

Originally posted by Pat Kelley:
You may have lower compression than you think. Cast pistons are usually .020" short and with an un-decked block and a rebuilder head gasket of .041", you are probably closer to 9.2, with a quench of .086". This is really really low for a 292º cam. It wants about 10.75-11:1. This is why it is a dog at low rpm. If the chambers are 62cc, which I understand many vortecs are, then the CR is 9.4, still very very low. I wouldn't put a cam bigger than a 272º in it. DCR with the 292 is 6.9 with a 64cc chamber and 7.1 with a 62cc chamber. Pat,

I got 9.5 compression number using .040 deck clearance and 6 CC four valve releifs. Bore is 4.030 and I did use the .041 gasket. I'm not sure the stock valve releifs are 6 CC, but you can correct me on that one. I used your calculator to come up with the number.

I've decided to go with the CC XE274-H which has a 274 duration on intake and 286 on exhaust. I've been told the vortec heads respond better to a dual pattern cam with more exhaust. Once I finish getting the best out of the present combo I'm planning to go with a new cam.

Something is out of wack. Did you try tuning what you have? Yes the cam is wrong (mine loves the XE series)but to be overcammed and have peak HP at 4800 RPM doesn't sound right. Vortecs build tremendous low and mid torque because of their design. Go back and take a good look at your present combo and do some playing.

Originally posted by Mike Feudo:
Something is out of wack. Did you try tuning what you have? Yes the cam is wrong (mine loves the XE series)but to be overcammed and have peak HP at 4800 RPM doesn't sound right. Vortecs build tremendous low and mid torque because of their design. Go back and take a good look at your present combo and do some playing. The peak was just under 5,000 but it did not drop off significantly as RPM climbed. Curve was fairly flat through 5,500 and it dropped after that. I'm not sure what else I can "tune", as everything seems to be correct including the timing curve and fuel.

Originally posted by m71:
</font><blockquote>quote:</font><hr />Originally posted by TJC:
Found my notes on the cam swap. ( 16 years ago... )

With HE272 ; 13.47 @ 105 idled at 15" of vac
BM2 ; 13.78 @ 101 idled at 12" of vac.

3600 lb Impala, 4.10 rear, 355, UNPORTED 492 heads, 600 Holley, torquer 2, 3000 converter.

Kinda fun reading those old notes. I recall how pissed I was at the results of that swap. Car went from being animal like, to limp noodle.... One other comment says "Passenger thought we had been rear ended" ( dropping from 3rd to 2nd on a roll ) what were your 60ft and 1/8mi times? you got 12" of vacuum with a torker 2 and that cam on a 355? that is impressive, no way you could have had that cam retarded. i think mine only made around 9 or 10" of vacuum and i had an rpm intake. :confused: i had the same gears and a cheapo Torkmaster 3000 convertor. car weighed 3760lbs with me in it. </font>[/QUOTE]I tried finding the time slips, but I couldn't. I used to keep pretty detailed notes when I was younger, but at that time I didn't understand the value of 60ft times. The vacuum readings are correct, but I may have had the cam advanced a few degrees. I was experimenting with alot of things to get that cam to work. I never was happy with it.
I also recall that the engine did not have much of a sweet spot, and like the original poster, it would fall on it's face over 5K. It was just a dull feeling motor overall.
I eventually installed that cam in a stock LG4 305, with home ported heads and it ran 14ohs with 4.10's. It actually ran stronger in that motor than the 350. Probably because of the smaller cross section of the 305 heads.

i do think an XE274 would be a better performing cam in your motor, but first thing i would try is a 3310 holley carb, then see what happens. do you know anyone who has one that would let you borrow it? i just don't think that cam is your problem. mine pulled pretty good until about 6000rpms, and if mine did that i don't know why any other 292 lunati wouldn't.

Originally posted by m71:
i do think an XE274 would be a better performing cam in your motor, but first thing i would try is a 3310 holley carb, then see what happens. do you know anyone who has one that would let you borrow it? i just don't think that cam is your problem. mine pulled pretty good until about 6000rpms, and if mine did that i don't know why any other 292 lunati wouldn't. The car does pull good to 6,000 in 1st and 2nd gear, but on the highway it really is nothing spectacular past 5,000 RPM. This is a 5 speed car with a TKO 500. With my combo I think the 600 CFM carb is about right for street driving. It it saw more strip duty then I could see moving up to a 750 or maybe a 650 DP. If I can get my hands on a 3310 I'll sure give it a try just to see.

i don't understand how it peaks at 4800rpms, but pulls to 6000rpms, that cam should be really peaky at around 6000rpms. something just ain't jivin'.

He, He!!

To nit-pick, the HE272 cam mentioned is an old Cam Dynamics cam that Crane now owns. (I think it's Cranes PN 272 H10 cam nowadays)..

Had one in my .040" over, 327 I gave my nephew!! Ran like a "scalded-dog" in that little about 10 to 1 CR. motor!!

I call it the "Little-Fireball" cam... (But there have been several F/B cams through the years as time passed)....

pdq67

PS., a side note: -- Crane does list their Powermax H-290 as the old "FireBall II 290H" cam in the older Crane cat. I have.

Spec's of both cams are;
272 H10 = 272/216, 110/105, .454" lift.

F/B II 290 = 290/216, 110/105, .454" lift.

I bought a General Kinetics 290 cam from Hollywood Sam's wayyy back when spec'ed the same as the above 290 cam and got to thinking about it and wrote them a note asking about the running difference between the two cams and the guy from G/K wrote back and said it was too complicated to explain in a short note but did say it was due to LCA theory differences in cam design.

I later went back to Hollywood Sam's and traded the 290 for the G/K 270 cam that was spec'ed the same as the C/D 272 cam above and it is now in the 327 I gave my nephew that is still sitting on his motor stand......

for one 3 inch exhaust is not going to help unless ya wanna go slower. bigger is not always better 3 inch shouldnt even be disgussed and the biggest problem anycar with a eldebrock carburator is severly in need of a holley all cars with performance type mods will always run better times and perform better with a holley. try a #3310 750 cfm vacume secondary and then use that eldebrock for a boat anchor thats all there good for. eldebrock makes some great performance type add ons and american made also but they should never have made carburators its giving them a bad rep for sure. any dyno guy worth pocket lint will tell ya that

g-k makes excellent cams the 270dur w/ 454 lift is great for bottom end and mid range then ya have there 282 dur w/ 488 lift great all around cam from low to high rpm then the 290 dur w/ 510 lift is a great mid to high rpm cam and all will work with factory type springs as long as the exhaust rotators are removed. ive been installing these cams on your average street motors since 1987 for the money i dont think theres nothing better for your average street racer with a budget . my 2 cents hope it helps

Superwrench,

Where do you get real G/K cams nowadays?

I thought Crane also ended up with them but don't remember?? I think Harold might have said something about it or somebody has somewhere???

pdq67

Originally posted by Rmchevelle:
</font><blockquote>quote:</font><hr />Originally posted by trimless:
Bottom line is that these VORTEC heads are great!graemlins/thumbsup.gif I look forward to the track results! </font>[/QUOTE]Here are the track results:

1.88
8.45 @ 82.66
13.29 @ 103.34

Ran through the mufflers and with a total of 38 degrees total timing.
That's a .6 second drop and 6 MPH gain over the previous best with the 76 CC heads! graemlins/beers.gif The track temperature was about 85 degrees and that's about 10 degree's hotter than the last trip, so this is very impressive to me. Not too shabby considering the "doggy" cam and "boat anchor" 600 CFM Edelbrock carb. I'm considering an XE 274 cam, but this Lunati cam may get me into the 12's with a set of slicks and some more tuning. I still had traction problems with my bfg DRAG RAIDALS. The 5 speed Tremec is hard to hook with it's steep 1st gear. Will a stock 8.2 rear hold up to a set of slicks and a 5 speed for very long?

:rolleyes: smile.gif

I think you may be overtimed. I've only done dyno work with Vortecs once, but on that particular combo, it was very happy with 32 degrees total, and didn't lose horsepower until we'd backed it off to 28 degrees. At 29 degrees it was making the same peak power, but torque was down slightly.

graemlins/thumbsup.gif Nice improvement!

Originally posted by trimless:
Not too shabby considering the "doggy" cam and "boat anchor" 600 CFM Edelbrock carb. :D :D :D

Originally posted by Greybeard:
I think you may be overtimed. I've only done dyno work with Vortecs once, but on that particular combo, it was very happy with 32 degrees total, and didn't lose horsepower until we'd backed it off to 28 degrees. At 29 degrees it was making the same peak power, but torque was down slightly. Hi Mr. Beard graemlins/waving.gif

I agree, every vortec head deal I have done has lost power above about 35 degrees
As I recall the last one lost like 15HP going from to 34-38 & was pretty happy from 30-34 with no measurable change in power which means at least in this case you would want it at 30.

For some reason this combo likes MORE timing. Initial is at 20 and mechanical at 18. I've run it at 30 to 35 total and the seat of the pants meter tells me that it's much slower at this setting. I didn't do any tuning at the track, but maybe next time.

The higher the advance the better off idle throttle response feel(seat of the pants) but not always the most power through out the range. I bet you pick up a couple of MPH with retarding the timing a bit.

You can accomplish both, by upping your initial , and limiting your mechanical. Say 20+14. I wont comment on why your engine likes so much initial timing. :D graemlins/waving.gif

Great numbers though. Especially with a low first stick.

I'd go ahead and phase the cam +4 like the builder says.

Originally posted by TJC:
You can accomplish both, by upping your initial , and limiting your mechanical. Say 20+14. I wont comment on why your engine likes so much initial timing. :D graemlins/waving.gif

Great numbers though. Especially with a low first stick. I know, a 3310 will help, right? I will definately try a holly before swapping cams. I'm using the black bushing on my MSD and that's 18 degrees mechanical. That the lowest mechanical advance that is offered in the kit. I'll call MSD today to find out if I can limit mechanical to 14 somehow.

427- yes, I think advancing the cam 4 degrees will help too.

I'd do one thing at a time. Work with the timing first as I'd bet money that 38 is at least 4 but more like 6 degrees over timed. If you fire a fastburn head to early, it won't always detonate but will first build up high pressure before you get to TDC, pressure or power that is wasted trying to stop the crank.

Leave the carb alone until you've got the ignition sorted as the carb showed to have a good fuel curve. Adding another change will confuse the issue. Always do one change at a time and compare. And if you can handle it, use the dyno. I'm very surprised the dyno operator didn't offer to do a test with different timing.

I would like to chime in and say my 355 with Vortec heads and CC 268H cam (.218 dur and .454 lift ran best e.t. and MPH with 32 degrees total timing.

Originally posted by New68SS:
I would like to chime in and say my 355 with Vortec heads and CC 268H cam (.218 dur and .454 lift ran best e.t. and MPH with 32 degrees total timing. Can you give us the ET/MPH? I always like to know what other people are doing.

Well, MSD wants more of my money! I called their tech line to find out that 18 degrees mechanical is a low as you can go with their billet disributor. The option they offered is to buy an MSD timing control and lock out the mechanical. So, to use what I have now would require running with 14 degrees initial to get to the 32 degree total. Don't think that it will run good at low RPM with that setting, but I'll give it a try.

Originally posted by New68SS:
I would like to chime in and say my 355 with Vortec heads and CC 268H cam (.218 dur and .454 lift ran best e.t. and MPH with 32 degrees total timing. What are you're details? I have a 355 with the same cam, kinda looking for comparisons

doh

Originally posted by trimless:
Well, MSD wants more of my money! I called their tech line to find out that 18 degrees mechanical is a low as you can go with their billet disributor. The option they offered is to buy an MSD timing control and lock out the mechanical. So, to use what I have now would require running with 14 degrees initial to get to the 32 degree total. Don't think that it will run good at low RPM with that setting, but I'll give it a try. With the two lightest advance springs in that MSD, you have all your advance in by 2000 rpm. And you have a manual transmission, so power right off idle shouldn't be a problem for you, as you can launch at 2000 or better. I think you should set the total timing at 34 degrees, do some track testing to verify that 34 degrees gives you best MPH, and go with it. 16 degrees initial should be plenty with a manual transmission.

Thanks Mike, what you suggested makes a lot of sense. Why didn't I think of that? :rolleyes:

Update: Got home today and re-set inital timing to 16 and then changed the springs out to get all mechanical in by 2,000 RPM. Holy Cra@!!! Bottom end response is MUCH better and top end is still there too. Runs much better overall. Good call Mike! I know there were others that told me I was overtimed too, you guys were all correct!

OK, I'm reseacring a set of slicks now, looking like I'm going into the 12's with this smallblock after all.

You're welcome, I have a new MSD Pro Billet also, and I have recently been experimenting with the same things.

I'll look at the time slips tonight an post them. They are not that impressive due to severe wheel hop off the line. I really had to baby her quite a bit at the tree. But, I do remember that she picked up several tenths with just the timing change. If I remember right, my 60' times were in the 2.50 range :(

The combo is:
'79 Z28
355 with Speed Pro hyper pistons
stock rods and rotating assm'y
Vortec heads with LT4 valve springs
stock manifolds ('79 Z28)
polished Power Plus intake
factory Q-Jet
factory GM HEI
stock exhaust(2 into 1 into 2 tail pipes with cat)
Comp 268H cam - .218 dur and .454 lift
4 speed with 3.73 gears

I know I'm giving up a lot with the factory manifolds and stock exhaust, and I'm sure the factory Q-jet is running small jets, but the idea was to keep her as stock lookin as possible. In fact without the Vortec heads shes pretty much a stock rebuild with a CC268H

With exhaust and some tuning on the Q-Jet, I know she could find another 20-30 horses.