Finally had a successful chassis dyno session. I drove my 72 Street/Strip Firebird to the Dyno AT SDCE Yesterday Morning. The last pass netted 666.9HP at 6200RPM, 654lb/ft at 5100RPM at the wheels. The A/F curve looked good, Staying in the 11's until the very end where it dipped into the low 12's. This was with 11.4 lbs of boost. The overall timing at 11.4 lbs was 25 degrees advanced. I did not try different timing Today. I am very pleased with the numbers and the way the car drives on the street. Here is the basic combo. Pontiac IA2 block , Forged crank(4.25"), Crower H-Beams 6.8", Ross Blower pistons(4.35 bore), Thanks Paul Spotts for a great 505" short block. The cam is a Comp 252I, 258E @.050 Around .600 lift with lash and 1.5 ratio shaft rockers. 112 installed at 108. The 87cc E-Heads flow 300 at that lift. The intake is an untouched victor and the Carb is a 4150 style from Pro systems. The Carb Hat is from SCDE. The headers are 2" Super Comps and It has a 3" exhaust with tailpipes. The air/fuel was a little rich at cruise and a little lean at the top end. So we went down in primary jet and opened up the PVCR. We went down in size on the hsab's. These changes worked great. My final jetting was 69 front and 80 rear. The blower is a F1R. No intercooler but a water/meth injection kit. The fuel system is an Aeromotive pump(A1000) with there 2 port regulator. 10an line form the cell to the regulator and a 8 an return and 8an vent. I think there is some left in this combo, I am not spinning the blower too hard. If I really wanted to step it up though I think I would need a F2? Thanks to all on the board who have helped along the way. Thanks again to Scott, Chris and Wendy at SDCE for all of your help getting my ride dialed in.

Chris Green

 

Good numbers man.....but watch the A/F if you're on pump fuel....low 12's is OK but maybe not the safest tuneup for an iron head Poncho.

-Carm

 

Thanks,

110 Race fuel and I run Edelbrock Aluminum heads.

 

And they only flow .300 @ .600, must be a Pontiac thing

-Carm

 

What do the Chevy heads in your Camaro flow?

 

I think he is saying that is low for a bigblock... They sound much more like smallblock head flow numbers.

 

For a while that is just about all we had (Pontiac). You have to move the pushrods and use offset rockers to get anything over 350 CFM with Edelbrock heads. Now there are choices that flow around 400 CFM out of the box ( one is a canted valve head) but they don't use off the shelf parts for Pontiac. John Langer uses the Tiger Heads and runs in the 8's NA in NMCA Pro Stock.

 

Congrats! good numbers! There is not too many blow-thru Pontiacs around! Would like to see some pictures of your set-up.

Mike.

 

I dont have a Camaro & my SBC heads flow more than that at lower lift

 

LOL stock L92 heads on a 6.2L flow 330cfm @.600 THATS a STOCK GM casting production head

 

Reasonably priced aftermarket Pontiac heads don't flow for shit when you compare to a good aftermarket SBC or god forbid BBC head. There's only so much you can do with the factory geometry. Thats why its so damn expensive to make good HP with a Poncho.

Good numbers for your combo though! Got any pics??

Craig

 

You must know him to come off like such a d!ck in your posts.

Sorry for getting sidetracked. Anyway, those are some decent numbers and it's nice to see another blow-through Pontiac. Don't be afraid of throwing some timing at that combo. The combustion chambers in the 87cc E-heads are notoriously lazy for flame travel, and typically respond very well to increased ignition timing. I wouldn't be surprised to see quite a large power gain with as much as 30-32 degrees of total timing with your combination. That may sound like a lot of timing, but most 87cc E-head Pontiac N/A engines usually run best with 40-42 degrees of total timing in my experience. Granted, that much ignition lead is a direct indicator of an inefficiency in the combustion process, but unless you go & weld up & reshape the chambers, that's just what we're stuck with. If you have room, I'd be interested to see what happened with experimentation with carb spacers as well. On that big of an engine, an unported Victor manifold has a bit of a small plenum area and would probably respond favorably with a spacer installed. Keep up the good work!

 

I just found this thread....thanks for the support Chris. You comming to the track on Wensday?.....the Monte is making it's debut.

 

Truth hurts eh?

Sorry for getting sidetracked

-Carm

 

Can't make it to the track this week Chris, Let me know how the Monte runs. How did it do on the dyno with more boost?

Carm, I called your "Firebird" a Camaro because you have a Chevy engine in it. Guess the joke went over your head.

 

590hp @ 6600 and 505tq @5000....cam is WAY to big. Stock block and cast crank is noooo good. I'm hoping for 10's and 130mph on wednsday. It's more than enough until I get the new bottom end and put the turbo on this winter/spring. I got whooped by a certain blue notchback on Saturday....gotta learn how to shift all over again, I was almost even and I missed 4th!!!

 

Like the fact that you could be running the same #'s with real Pontiac power in your Pontiac, and it could be done with factory iron heads that flow even less than your SBC heads that already are E-head killers? Yes, I suppose the truth does have at least a little sting to it. :-X

 

Any pics of the engine?

Great combo and power for only 11psi and 25 degrees. I'd suggest running straight Methanol so it can help fatten up the WOT tune, can you post the specifics of the alky kit for us. If you are running a single nozzle an easy way to fatten up and turn up the boost is run two 15gph nozzles on a progressive kit turning on around 2psi.

Raising the boost on a big block will make more power than timing so start there first and watch the power really climb as you get towards the 20psi range and 25 degrees.

I also agree with SDCE, cam is WAY WAY to big for a car probably spinning 6400 tops with that stroke crank and you've advanced the cam pushing the power up even higher.

Pontiacs have two big heads now which can give mid 400cfm ported but Edelbrocks at 300cfm at .600 is lame for you BBC guys but our reality.

 

His a/f curve was just about perfect when we were done with it. I would never recommend running straight methanol through the nylon push-lock hoses that the Snow kits use...you are asking for a leak, or a melted tube.

The cam I was talking about was my motor, Chris's power comes in a little high also, but it is a built engine that he says will take the rpms. And i'll agree with you on the heads, 300cfm is a weak for a BB; but when he wants to get more power out of it he knows where we are .

 

great #'s-cool to see diff engines running blowthrus-seem to be more Pontiac's with them now, making great power