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454 (.030), 10:1cr, Air Gap, Brodix 270 RRO, Clay Smith 229/241

58K views 218 replies 46 participants last post by  shovelrick 
#1 · (Edited)
1/12/2021 UPDATE
Final engine combo and dyno results Post #136
Maiden voyage in my car Post #163

3/16/2022 UPDATE
First day at the track Post #168

11/21/22 UPDATE New Best ET/MPH
Final track results

****
So I am patiently awaiting a PM response from a well known cam designer here (regarding the cam below) and thought I would post this to the board to get your thoughts as well. After much searching here, it seems like a fairly solid combo but I could be missing something. Looking for thoughts on the compatibility of the cam (pretty sure its gtg), and recommendations on roller lifters, and a stall converter and carb to match.


Clay Smith Grind # HR-8800-9-CSR
Adv. Dur 288/300
.050” Duration 229/241
.200” Duration 145/151
Lift .590/.570
Centers 105/113
LSA 109

...with the following build:

My car is ~4000# in full trim with me, a spare tire, jack, and a fairly empty gas tank according to track scale.

10:1 CR, 454 +.030 (~460 cid)
Air Gap intake (have a spare Wieand Stealth RP from previous combo )
Carb undecided (have a spare 770 SA and QJ on hand. May purchase an 850 QF?)
781's 2.19/1.88, 118cc chamber (measured), long slot steel rockers, mild clean up (no porting), gasket match
Sealed Power Hyper -22cc
Appropriate head gasket to set quench to ~.039-.040 or so (block has not been decked, need to check piston depth)
Stock crank (cast) and rods w/ARP bolts
Desired max RPM 6000



Replace existing 1-5/8" headers and 2.25" exhaust with 1.75" headers into 3" collector, 2.5" all the way back, mufflers undecided...

TH400, (soon to be) rebuilt with Hughes Performance kit Jakes Performance Stage II kit, upgraded 34 element sprag
Replace stock converter with 3000 stall converter ... open to recommendations here. Not sure exactly what would be best fit for the engine.

8.02 open 3.36 rear gear on a 26" tire (215/70R14). This whole set up may get replaced (another story) but I would like to stay with the same gear. Stock suspension all around with poly bushings front and back.

If you need more detailed please ask. This is a street/strip car that I drive like I stole it about 1000 miles a year. It cruises down the highway at about 3000 rpm. I ran ethanol free 93 octane for about 13 years on my previous 9.3cr 215/219 peanut port build. Great little combo but I am ready for a massive somewhat budget oriented change while I have everything out of the car. I believe this will out perform my previous combo. Trying to get into low 12's eventually (whenever I upgrade the rear end).


Thanks,
-Kevin
 
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#134 ·
Will you be posting your dyno results.
I have almost the identical combination, but never had mine dyno'd. So I'd really like to take a good look at your results thx.
 
#135 ·
Yes I sure will. Havent had time yet trying to wrap up a few other concurrent projects.
 
#136 · (Edited)
Sorry for the delay. Been really busy here. Attached are the graph and data from run #5 (max torque day 1) and run #11 (max power day 2) where we zinged it to 6k as we still hadn't seen max power.

As you can see, the final run is down 5-9 hp/tq in various parts of the rpm range which he chalked up to a "hot run". Indeed the second to last run (run #10 also on day 2) was on par with run #5. Had we ran it to 6k on run #5 I think there would be some more power there. Either way, this thing came out awesome and should perform very well in my "big chevelle". I'll be upgrading the drive train in August when my piggy bank is full again :smile2:. I dont think my 8.2 open differential is up to the task. That will be the subject of another post.

As far as budget, for those wondering, I am on par with the iron headed 570hp/580tq 467cid Vortechpro has listed on his website. I haven't done a final tally yet but if I do I will be sure to post that as well.

That kinda concludes this thread but feel free to ask any questions or PM me.
-Kevin

<edit 12/3/2021 - reposting dyno info due to it disappearing>
Dyno graph
Rectangle Slope Plot Font Line


Dyno run #5 - Max torque achieved (did not run to 6000 rpm)
Font Material property Parallel Pattern Screenshot


Dyno run #11 - Max HP achieved (may have seen more on run #5 if we took it to 6k)
Font Material property Screenshot Rectangle Parallel


10:1 CR, 454 +.030 (~460 cid), 4 bolt, square/deck to 9.790
Intake Air Gap RPM
Ignition MSD Streetfire HEI (with an Accell BruteThunder HEI super coil to replace failed OEM coil)
Cam Straub BBC Retrofit Hydraulic Roller .050 229/241, Adv 288/300, lift .600/.570 with 1.7 rocker, 109 LSA (thanks CStraub)
Lifters Morel 5374 roller lifters, 3/4 turn pre-load (thanks CStraub)
Carb AED 950 HO BK double pumper, 820 CFM (thanks CStraub)
Heads Aluminum Brodix RRO 270, non-CNC option, 2.25/1.88 valves, 165#/385#, fully assembled
Studs ARP 2.10", 7/16-20 thread (334-7203)
Rockers Comp Ultra Pro Magnum 1.7:1
Push Rods Manley 3/8” push rod, one piece, .080” wall with 5/16” ball ends (25879-8, 7.875"; 25887-8, 8.875")
Pistons Racetec forged, 22.7 cc dome, .010" offset floating pin ~ zero deck (thanks Wolfplace)
Rods 6.135" Scat I-Beam w/ARP hardware (thanks Wolfplace)
Crank Stock GM cast crank
Timing Set Rollmaster Gold Series CS2040
Oil Pump Melling (standard volume I believe with 4qt pan... no oil control issues on dyno)
Desired max RPM 6000, Goal 525/550

 
#138 ·
Sorry for the delay. Been really busy here. Attached are the graph and data from run #5 (max torque day 1) and run #11 (max power day 2) where we zinged it to 6k as we still hadn't seen max power.

As you can see, the final run is down 5-9 hp/tq in various parts of the rpm range which he chalked up to a "hot run". Indeed the second to last run (run #10 also on day 2) was on par with run #5. Had we ran it to 6k on run #5 I think there would be some more power there. Either way, this thing came out awesome and should perform very well in my "big chevelle". I'll be upgrading the drive train in August when my piggy bank is full again :smile2:. I dont think my 8.2 open differential is up to the task. That will be the subject of another post.

As far as budget, for those wondering, I am on par with the iron headed 570hp/580tq 467cid Vortechpro has listed on his website. I haven't done a final tally yet but if I do I will be sure to post that as well.

That kinda concludes this thread but feel free to ask any questions or PM me.
-Kevin







10:1 CR, 454 +.030 (~460 cid), 4 bolt, square/deck to 9.790
Intake Air Gap RPM
Ignition MSD Streetfire HEI (with an Accell BruteThunder HEI super coil to replace failed OEM coil)
Cam Straub BBC Retrofit Hydraulic Roller .050 229/241, Adv 288/300, lift .600/.570 with 1.7 rocker, 109 LSA (thanks CStraub)
Lifters Morel 5374 roller lifters, 3/4 turn pre-load (thanks CStraub)
Carb AED 950 HO BK double pumper, 820 CFM (thanks CStraub)
Heads Aluminum Brodix RRO 270, non-CNC option, 2.25/1.88 valves, 165#/385#, fully assembled
Studs ARP 2.10", 7/16-20 thread (334-7203)
Rockers Comp Ultra Pro Magnum 1.7:1
Push Rods Manley 3/8” push rod, one piece, .080” wall with 5/16” ball ends (25879-8, 7.875"; 25887-8, 8.875")
Pistons Racetec forged, 22.7 cc dome, .010" offset floating pin ~ zero deck (thanks Wolfplace)
Rods 6.135" Scat I-Beam w/ARP hardware (thanks Wolfplace)
Crank Stock GM cast crank
Timing Set Rollmaster Gold Series CS2040
Oil Pump Melling (standard volume I believe with 4qt pan... no oil control issues on dyno)
Desired max RPM 6000, Goal 525/550

Nice work! :thumbsup:
You have to report back how it feels and runs in the car.
 
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#137 ·
Since you mentioned me lets compare, the 570HP 467 was originally designed with a Isky 280 Mega cam, which is a 232 @.050, .550 lift hyd flattapet cam, it used a Icon piston with a 5/64 ring pack. Your dyno data is a fairly good representative of that combination. But-when the customer upgraded to a hyd roller 228/238 and a Mahle piston very similar to the racetec piece you run this is the results I see:
 

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#139 ·
I should clarify, I was not implying mine was better in any way. Mine has different parts. It was simply a comparison for comparisons sake on hp/tq and cid for the dollar. More than likely apple's to oranges and more than likely I am dollars behind vs just buying that combo off your website.

I love reading up on your builds and fully respect and would recommend you to anyone. Sorry if that came out any other way Mark.

-Kevin

PS Those are very impressive numbers!
 
#142 ·
Very nice torque curve!

Couples of questions:

1) Why not spin it higher? HP was still climbing, no valve float, parts should easily handle 6300.

2) 4 qt oil pan? I think stock BBC is 5 qt. Do you plan on running 4 qts once it's installed?
 
#144 ·
1) 6000 was my goal. Perfectly comfortable stopping there and the gains beyond that are probably negligible.
2) I planned to change to a larger pan but did not have time to order and ensure correct fit so i ran my existing pan for the time being. Edit - the pan is a 4qt but I run just under 5qts after the filter consumes a little.
 
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#146 ·
Thank you sir.
 
#154 ·
Thanks Rick! I'll be following your progression on yours.
 
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#149 ·
You did REALLY well Kevin! Excellent build!


I say that having one of Mark's upgraded 467s, VERY close to the above results. Brother I dont think I would have come close here locally, especially not with the very mild street manners of Mark's build. (other than stroking it, which I wasnt keen on.)

Expect that displacement and your Straub cam is very similar! Somewhat mild mannered and a BEAST WOT. Can't wait until you strap that heart back in and hear it beating between the rails!

:thumbsup:
 
#153 ·
Yes. I wanted zero deck but didn't want to take a full .020 off the block so I had them square it to 9.790 and pushed the piston up .010 to meet it. Mike Lewis actually suggested this to me when we were chatting about pistons. I didn't know it was an option prior to that.
 
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#163 ·
UPDATE

Not trying to revive this thread or anything but did at least want to provide an update.

Last January (2020) I pickled my new engine between the fenders of my car and went out of town for 9 months. Came home, tackled dozens of honey do's and then my wife and I yanked the pickled engine, separated the TH400 transmission and set to work rebuilding it. Jakes Stage II rebuild Kit, 34 element sprag, a few other mods, yada yada, and an Edge 3500 stall converter. New experience for both of us. Took our sweet time. Great fun.

Got the transmission mated to the engine and stuffed everything back between the frame rails. Installed fenders, rad support, wiring, fuel, cooling, new hood springs... I should have replaced those a long time ago... best day ever. Re-used my road dented 1-3/4 headmans and 2.25" dual exhaust, and the original thrashed 8.2 gm rear with 3.36 gears.

All that to say, I got her fired up last week. Sounded just as sweet as it did on the dyno a year earlier. Unfortunately, the mechanical fuel pump died so it would only run until the bowls went dry. Pump was removed two years ago when I started the rebuild and set on a shelf. I should have just replaced it.

Anyway, ordered up a Carter 120 gph mechanical and plumbed it up. Engine fired immediately. Set the timing, addressed some fuel leaks, topped off fluids, let it run for another 30 minutes or so to check everything out. No leaks, no overheating, good oil pressure, good charging, and my home built transmission engages forward and reverse! The engine still has a VERY snappy throttle response.

After convincing myself there is nothing I was forgetting and getting over my anxiety, I took it on its maiden voyage down my street. This car is a totally different animal now. Unbelievable how much more power I have on tap. It's stupid really. I am super happy with it and cant wait to test on it some more.

Still have some minor tuning to do, some parts to put on the car, headers, exhaust, and rear end to replace, and then we'll really open it up.
 
#165 · (Edited)
<edit> previous engine was the same 454 i am running now... well same block, crank,, and oil pan.. bored .030 over now

<edit#2> corrected hp estimate of old combo

old 454 peanut port combo... Guessing 300 hp based on a few online calculators using weight ~4100# and 98 mph trap speed. Cam was a 215/219 lunati hydraulic flat tapper.

Non CNC chamber option on the heads. The whole combo is in POST #136.
 
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#166 ·
Don't be afraid to have the carb and distributor tuned at a local shop, assuming you can find one.

FWIW, I think you should trap at over 110 in the 1/4.....likely even higher.
 
#168 · (Edited)
First day at the track

Sheesh how time flies... some quick update in case I didn't cover it before. Since last August...

1) I had multiple brake cylinder failures (on one occasion, both a front and rear went out... drove home with the e-brake... always maintain your e-brake people!). All new soft/hard brake lines, new brake cylinders, shoes, turned drums, replaced front wheel bearings... stops like a champ now and does not leak anywhere which is important.;)
2) Outer bearing failed on my 8.2 rear end. Yanked the rear end and wrung out my wallet and installed:
- Moser 12-bolt, 3.73 gears, 35 spline bolt in axles (with GM pattern housing), 5/8x3" screw in studs, Wavetrac Helical/Torsion Differential, Aluminum Girdle.
- Global West double adjustable UCA (added driver side UCA as my car was originally equipped with a single passenger UCA) and UMI 2-hole brackets on the frame
- New 3.5" steel driveshaft, 1350 joints front and back
3) And most recently, put on a set of borrowed 26" 275/50 drag radials for track day

Suffice it to say, nothing should break back there. If I recall correctly, I believe I set the pinion about 1 degree down from the transmission (i.e. when torque is applied, the pinion and transmission angle should be the same but opposite in relation to the drive shaft).

I scaled the car and adjusted the passenger UCA slightly. I didn't hit the scale at the track but I am estimating 3950# with me in it?
No driver, Removed spare tire and jack. ~1/2 tank gas (?)
LF
992, 26.6%, RF 1005, 26.9% Total Front 1997, 52.6%
LR 869, 23.3%, RR 869, 23.3% Total Rear 1738, 47.4%
TOTAL 3735#

My worst run was 12.6 @ 104.9.
Here is my best run except where indicated:
60' 1.779 (best was 1.716 on run #5)
330' 5.014 (best was 4.975 on run #5)
1/8th 7.772 @ 88.6 mph
1000' 10.196
1/4 12.297 @ 105.78

Track summary/notes:

  • Track was approximately 65 F, Humidity 13%, Baro 28.8, light winds.
  • I got in 5 shakedown passes over 4 hours (3.73, TH400, 26" tire, 3500 stall). Times were all over the place due to my inconsistent driving, in particular, my shift points.
  • Experiencing what feels like a momentary loss of traction off the line on every run. A split second slip then it hits. Can hear the screech in video and can see it on the tach in the one instance I managed to film it with my phone in my shirt pocket. Not sure what is going on here yet (i.e. one or both tires slipping).
  • On run #2 engine started to back fire at the stripe... thinking fuel starvation (stock system other than Carter 120 gph mechanical pump. Problem did not reoccur.
  • Watching slo-mo on the drivers side, to my surprise, I am getting separation (anti squat) on the rim. Not sure about the passenger side.
  • Drag radials set at 19psi, stock shocks/springs front and back
  • Calculated ~12.9% converter slip with tires and gearing at 5900-6000 rpm
  • All launches were ~2000 rpm except for run #5 which was ~1600 rpm or so? I didn't really catch it but it was less. This resulted in my best 60 ft time shown below.
  • All shifts were about(?) 5900-6000, again, difficult for me to watch and honestly I was nervous at 6000 even though it exceeded that on the dyno.
  • On run #4, I raced my buddy and held on a little longer to a solid 6000 rpm. This resulted in my best ET and MPH

I was not expecting to reach my goal (and I didn't) but there is more et to gain here. Exhaust was on my list. Just haven't got around to it and I thought it would be a nice before/after comparison.
So in no particular order...
  • Replace 1-3/4 headers, full length 2-1/4" dual exhaust, and FM40's, with 1-7/8 headers, 3" dual with X-pipe, and undecided mufflers dumped before the axle
  • Find best shift RPM (and be consistent)
  • Find best launch RPM
  • Find best timing/jetting after new exhaust

Curious what kind of potential gains you see here.

I think that's everything. More to come.

Haven't got all my trim back on the car but here is my (un)glamor shot
Car Tire Wheel Vehicle Automotive parking light
 
#169 ·
That car has high 11's (if not more) in it like it fell out of a tree.
One thing I noticed is you are only picking up 17.1 MPH on the back half.
Should be 20-21 MPH at a minimum.
The exhaust will help big time, I would make a pass with the exhaust disconnected.
Either you are letting up before 1/4 mile stripe or something else is wrong.
Here is a pass with my GF's 69 SS396 (12.15 pass on left) , this is a 8.9:1 +.030 454, 238/248@.050 Summit cam,RPM AG/750 DO,TH400/3500 stall 3.42

Receipt Font Material property Paper Number
 
#171 ·
Yeah I noticed the back half gains too and attribute that to my exhaust. I just dont think it's breathing. I intended to unbolt it but was so amped up I forgot. Launching on drag radials with this much more power was a real eye opener for me. Wish I could have filmed my expression through first gear!

Hey Kevin, Double check that you are getting WOT! I think 22 -26 mph gain in the back-half is about right. Also, you need to keep a close watch on your fuel pressure. If it drops off too much on the big end, could be big trouble. Be careful.
Yes, checked that they day before and the throttle plates are straight up and down. Whether I was jamming the pedal all the way into the floor is another story. Guessing my exhaust is holding me back as previously mentioned. We'll see. I do not have a fuel pressure gauge but may install an AFR meter with the new exhaust. I also have a new sock/pickup for my gas tank but have been tossing the idea of adding a small fuel cell in the trunk (with new lines to the pump) and draining the big tank for racing.
 
#170 ·
Hey Kevin, Double check that you are getting WOT! I think 22 -26 mph gain in the back-half is about right. Also, you need to keep a close watch on your fuel pressure. If it drops off too much on the big end, could be big trouble. Be careful.
 
#172 ·
IMHO, your fuel system is fine. My GF's 69 just runs a stock tank and a $22 AirTex parts store fuel pump. If her car had your 1.71 best 60 ft. that 12.15 pass would have been 11.9X
I think, going by your 1000 ft. ET and then your 1/4 ET's MPH that you are letting up before the stripe.
Your car will be in the 11's before you know it 👍 Looks great by the way!!
And you NEED to jam the pedal to the FLOOR!! :)
 
#180 ·
IMHO, your fuel system is fine. My GF's 69 just runs a stock tank and a $22 AirTex parts store fuel pump. ...
Your car will be in the 11's before you know it 👍 Looks great by the way!!
And you NEED to jam the pedal to the FLOOR!! :)
I will be pushing harder the next time. And thank you for the compliment.
I can lend a little advice on the 3" exhaust. I installed a full length (to the bumper) 3" exhaust on my 67 Impala. ....
I am still tossing ideas around here. Excellent info on the B-body exhaust. Thank you! My plans I had for dumping at the axle were temporary and for convenience sake. I would eventually run them out to the bumper so your info is quite helpful.
First I'll say I love your detailed report. It's enjoyable to read.
Thank you. Just trying to learn and give back at the same time.
The weight of your car surprises me in a good way. I did not expect a big car like yours to be that light. I'm like 3760 with a full tank of gas and no driver. Also really impressive weight distribution.

Having said that, your car should MPH a LOT more. That 2.25" exhaust is killing the power for sure, I'd guess it'll be night and day when you move to a full 3". I suspect the tune could be off too. I don't think it'd hurt to chassis dyno the car once you get the 3" exhaust on. I understand that your car is an auto and mine is a manual, so you will see more driveline losses than I do, but it is possible the transmission losing more than usual. I've chassis dyno'd mine at 370 rwhp, and even with the 4000 ft DA air we see here, I can still hit around 107 mph trap speed. I'd expect your car to trap closer to 115 mph.

First time out, 12.297 with just a 105.78 mph trap speed shows that thing is boogying in the front half. Your dyno results showed a torque monster, and that seems to show in your ET. Can't wait to see you get the car sorted because 11s are going to be no problem in your future.
I was surprised as well. It was 3964# with me in it and the spare tire/jack still in the trunk. The only weight reduction the car has is in the headers and aluminum heads/intake.
I don't think the exhaust system is your problem. My 496 with Brodix RR Ovals and an Isky hydraulic roller (228/238 @ .050) went a best of 11.37 @ 117 with a 60' time of 1.59.

My headers were the Summit brand 1.75" headers they were selling at the time for $99, with a complete 2.5" street system bent by a local muffler shop, all the way out the back from there.

Transmission was a TH400 with 2800 stall, and 3.42 gears.

All that said, my first pass off the trailer with the new engine described above was 12.40 at 110mph I think. You just need to tune.

I agree completely with Mr 4 Speed that you should be gaining 20-21mph between the 1/8 and 1/4 mile. Can't say that I agree with the other post that it should be 22-26mph gain, I've never seen more than 20-21 on any car or combo I have raced.

My best advice - DON'T SPEND ANY MONEY YET! Experiment with timing and carb tuning. You should be at least 90-92 mph in the 1/8 mile, and 110-112mph in the 1/4 with you car exactly as it sits. Carb jetting & ignition timing SHOULD get you there. I also don't really think you have a fuel pump issue. I have experienced a fuel pressure issue (the strainer on the pickup in the tank was clogged) and the engine simply quits when that happens. My 11.37 @ 117mph was with a mechanical pump and stock fuel supply system.

LOVE you car - I have a 65 Impala. Good luck and keep us updated!
Thank you for the compliment. I'd be interested hearing more on your tuning between your 12.4 and 11.37 et's. That's impressive and encouraging. How many passes did it take to get there?
I dont disagree about tuning before spending money but the exhaust replacement was always in my plans (for years actually...yes it takes me a while to get things done). 2.25" is just puny and it's not in very good shape overall. I would rather dial it in once (assuming a header/pipe change would affect my tune). It would make a nice before/after comparison though. Depends how many times I want to drive to the track which is pretty much an all day affair.
On the fuel, I meant to imply that my sock/pickup may be clogged. Pretty sure it's 50+ years old. The backfire only happened on the one run so I will likely change out the sock and press on based on comments here.

Kevin if you fmdon't mind a little loud check into Pype Violators, I have 3" X Pypes exhaust to the bumper, you can look straight through the Violators :) theres a sound clip on youtube Shovelrick1
I dont mind loud. I think "louder" is what I am trying to avoid. Not 100% sure what direction I will go here.
This car has gone 13.22 @ 101 with a 355 (vortec heads and a small hydraulic roller cam), TH400 with 2400 stall, and 3.55 gears. You will go MUCH quicker than your first passes when you get carb & ignition right. This rig weighs 4000# with me in the seat.
That's a boat load for a 355. Nice work!
Based on the strong 1/8 MPH, I bet Kevin lifted BEFORE the 1/4 mile stripe. I have a few friends that have done this as well. Not on purpose. It happens.
And also, you need to go to WOT immediately and hold it there.
Real world experience:
I drove a friends car and went 11.94@121 MPH leaving on a soft 2.05 60 ft. (didn't want to hard launch as its not my car, a 1986 Grand National)
He drove it and it went 12.5@110 MPH and he didn't floor it.
I did
I told him if I drove it the way I wanted to, it would have ran low 11's
lol... I will bury that pedal next time, I promise.
Long thread but looks to me like there's A LOT of mph missing on the front and back half. Need to find it.

For comparison, my 454HO @425hp ran 107.5 mph @4000lbs - cant remember the 1/8mph

ZZ502 @502HP in a full weight Chevelle runs high 11's @112-113.

Need to check over everything - full throttle, make sure timing didn't move, plug wires/miss, trans fluid, brake drag etc.
I debated starting a new thread but opted to keep the story rolling. I do put links to various "milestone events" in Post #1 so people dont have to scroll through 20 pages.
Anyway, I've seen a bunch of your threads and you (amongst many others) are pretty good at putting the power down. I will be checking all of these things.
 
#173 ·
I can lend a little advice on the 3" exhaust. I installed a full length (to the bumper) 3" exhaust on my 67 Impala. At the time, approximately 1.5 years ago, there was no kit available in 3" to fit these cars. Largest kit I found was 2.5". Anyhow, I got a universal 3" kit with mandrel bends and custom built mine. If you wanna go over the axle, you can run 3" tubing down beside the gas tank, (much easier to install this way) instead of running it back under the frame and tucked up next to the quarter panel and dumped out close to the taillights. You'll have to dolly/massage the flanged seam on the gas tank either up or down to make the room, but it'll fit. If you run it out the back, it'll be much quieter inside the car, I see you have it tagged, so you might appreciate that if you do much street driving. As for mufflers, that's wide open for debate. Pick what you want, but personally, I'm a Borla guy. I'd recommend the ProXS, as they have the offsets you'll need if you wanna go over the axle. They are a straight thru design and have a great tone at idle and part throttle but jump on it and they get loud! Next, X pipe or H pipe? Again, personal preference, but it kills me to hear a raspy sound from a classic car such as yours because of the X pipe. The H pipe will give you that classy old school sound that can't be replicated with the X pipe. Good luck and I absolutely love your sedan. Keep the updates coming.
 
#174 ·
First I'll say I love your detailed report. It's enjoyable to read.

The weight of your car surprises me in a good way. I did not expect a big car like yours to be that light. I'm like 3760 with a full tank of gas and no driver. Also really impressive weight distribution.

Having said that, your car should MPH a LOT more. That 2.25" exhaust is killing the power for sure, I'd guess it'll be night and day when you move to a full 3". I suspect the tune could be off too. I don't think it'd hurt to chassis dyno the car once you get the 3" exhaust on. I understand that your car is an auto and mine is a manual, so you will see more driveline losses than I do, but it is possible the transmission losing more than usual. I've chassis dyno'd mine at 370 rwhp, and even with the 4000 ft DA air we see here, I can still hit around 107 mph trap speed. I'd expect your car to trap closer to 115 mph.

First time out, 12.297 with just a 105.78 mph trap speed shows that thing is boogying in the front half. Your dyno results showed a torque monster, and that seems to show in your ET. Can't wait to see you get the car sorted because 11s are going to be no problem in your future.
 
#175 ·
I don't think the exhaust system is your problem. My 496 with Brodix RR Ovals and an Isky hydraulic roller (228/238 @ .050) went a best of 11.37 @ 117 with a 60' time of 1.59.

My headers were the Summit brand 1.75" headers they were selling at the time for $99, with a complete 2.5" street system bent by a local muffler shop, all the way out the back from there.

Transmission was a TH400 with 2800 stall, and 3.42 gears.

All that said, my first pass off the trailer with the new engine described above was 12.40 at 110mph I think. You just need to tune.

I agree completely with Mr 4 Speed that you should be gaining 20-21mph between the 1/8 and 1/4 mile. Can't say that I agree with the other post that it should be 22-26mph gain, I've never seen more than 20-21 on any car or combo I have raced.

My best advice - DON'T SPEND ANY MONEY YET! Experiment with timing and carb tuning. You should be at least 90-92 mph in the 1/8 mile, and 110-112mph in the 1/4 with you car exactly as it sits. Carb jetting & ignition timing SHOULD get you there. I also don't really think you have a fuel pump issue. I have experienced a fuel pressure issue (the strainer on the pickup in the tank was clogged) and the engine simply quits when that happens. My 11.37 @ 117mph was with a mechanical pump and stock fuel supply system.

LOVE you car - I have a 65 Impala. Good luck and keep us updated!
 
#177 ·
This car has gone 13.22 @ 101 with a 355 (vortec heads and a small hydraulic roller cam), TH400 with 2400 stall, and 3.55 gears. You will go MUCH quicker than your first passes when you get carb & ignition right. This rig weighs 4000# with me in the seat.
 

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#178 · (Edited)
Based on the strong 1/8 MPH, I bet Kevin lifted BEFORE the 1/4 mile stripe. I have a few friends that have done this as well. Not on purpose. It happens.
And also, you need to go to WOT immediately and hold it there.
Real world experience:
I drove a friends car and went 11.94@121 MPH leaving on a soft 2.05 60 ft. (didn't want to hard launch as its not my car, a 1986 Grand National)
He drove it and it went 12.5@110 MPH and he didn't floor it.
I did
I told him if I drove it the way I wanted to, it would have ran low 11's
 
#179 ·
Long thread but looks to me like there's A LOT of mph missing on the front and back half. Need to find it.

For comparison, my 454HO @425hp ran 107.5 mph @4000lbs - cant remember the 1/8mph

ZZ502 @502HP in a full weight Chevelle runs high 11's @112-113.

Need to check over everything - full throttle, make sure timing didn't move, plug wires/miss, trans fluid, brake drag etc.
 
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