What woudl it take to get a 1968 Firebird weighing 3330lbs (prolly 3500lbs race weight) to go 12.8 in the quarter mile on DOT tires? How much horsepower, it will be a DD as well. All help apreciated.

 

About 425 hp should do. Pontiac power?

 

My 80 Camaro could run that with it's 430hp crate engine. The car just needs a little more torque converter so it can get off the line better.

 

Yes, it's a poncho motor. Now, since it will be street driven a 425hp 350 (well, 356) pontiac will still return better mileage than a 425hp pontiac 400... right?

Also, suspension? Is currently stock, should I bias the leaf springs? What should I do to get the power to the ground?

 

let's discuss offline to avoid harsh judgment
I'll be happy to offer suggestions - but you may not want to hear some things - 30 years building Pontiacs and I am "chief455" for a reason lol!

pm me...

 

Like Chief alludes,
you might not like to hear this, but a 425 HP 356 might not get better mileage than a 425HP 400. The reason being that you will have to tighten up the powerband on the 356 in order to hit that 425 HP mark. You in essence will give up low-end torque in order to gain top-end power. Since most cruising is done at sub-2500 RPM, your high-strung 356, which will be designed to make 425 HP much further up the RPM band, might have to work harder at cruising speeds than something with more CID which will have a flatter torque curve.

Of course, a lot depends on the execution of the engine design: With the right heads & valvetrain configuration, your 356 might yield awesome performance and great mileage, too. Personally, I'd opt for more cubic inches so that you can have 425 HP and street manners as well.

 

When you're dealing with "old school" - gas economy needs to be mostly left out of the equation. If you wind up getting decent ecoomy - great, but if you get your power/speed goals - better.

I have yet to see or personally build a 326 over 400hp/tq that was as economical and reliable as a 400 or 455 making the same power.
It can be done - no doubt - but at far greater expense and "outside the box" configurations.
A 400 or 455 can be built on a budget and pretty easily move your weight car into the 12's.

 

post some questions over at Performanceyears.com/techforums


They are a very knowledgeable group on Pontiacs (real, not corporate) over there.

 

great place to get any parts you need as well. New and used performance Pontiac parts flow like water there

I know - I've sold and spent thousands

 

Won't be easy getting that kinda power out of a tiny bore Pontiac 350...

 

With a well prepped and lightweight rotating assembly, ported < 72cc heads from a '60s 400 w/ 2.11 intake valve, a custom ground flat tappet or roller cam and the usual intake / exhaust upgrades as a 400/455 - a 350 could be forced to make 400hp.
The reality is - why bother?

 

I might be wrong but I thing were making things too complicated. I'm an engine guy so I always like to make more power but if you want to run 12.8's you need to first look at your suspension. Google Cal tracs and call him. He can set you up with the right leaf springs and shocks that will really help you hook up the car. A decent gear ~ 3.55 makes a big difference. A mild rebuild with a modest cam about 224/230@ .050 and the right valve springs. Adjustable rocker arms. minor port work. Do what you can to get your compression up to 9-9.25:1. Performer RPM intake and a holley 650dp carb. Add a 22-2400 stall converter good for a daily driver and subframe connectors. If you can find a convertible x brace for under the car cheap then that would help as well. (Chief didn't think I knew bout that one...) It shouldn't take you more than 300rwhp to run 12.8 at that weight if the car is right. I ran 12.8's in a 2900lb car making 204rwhp and 12.3 in a 3100lb car with 350hp. It's all about how you set it up.

BTW, my first muscle car was a 69 firebird convertible with a 2bbl 350 so I've been down this road...

 

Rev iis on it Maybe I'm not the only old guy in here !

I had a pm from the orignal poster - would rather talk on the phone as the motor would be his first.

http://www.calvertracing.com/

These were on the last 3 leaf spring cars I built - the best streetable hook for your dollars with a good Pontiac based (not off the shelf) convertor = done.

69 Firebird coupe, 355 rear, TH400, garden variety 455 with mild port job and 225/231 - .535/.545 lift on a 112LCA, Performer RPM, 800DP with a 2800 stall, full weight body shifting at 5,000 trapping at 5,200 get's 12.6 all day long on drag radials. That was a throw together car on spare parts.

I agree - the 400hp number if fun to talk about but a factory 335hp rated 400 car could easily be in th 12's, it's in the combination and weight.
If originality is not of a concern, dollars and sense say build a bigger motor to help everything work easier. If the 350 is a must have - maximizing the entire combination will be critical.
I am still pretty lost with these computer cars - I wish I were building an old car - it's just so basic and quickly rewarding!

 

I forgot to mention - though it should be in the classified zone - that I have a Pontiac 400 for sale if anyone needs it...cheap!

 

I've narrowed my criteria on how I'd like to get 12.8s:
It will be no larger than a stock-stroke 400.
I will use a quadrajet, (and most likely modify a q-jet manifold a la Jim Hand or Bryzinski)

There isn't any specific reason, if I were to have built a car w/o whims and stigma I doubt I would be working on a rusty '68 Firebird.

I all for a cal-tracs suspension. Just to make sure, I will be sacrificing corning ability in exchange for straight-line traction... right?