I want 12.8 timeslips

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?

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.

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.

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 :eek::eek:

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

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?

I've narrowed my criteria on how I'd like to get 12.8s:
It will be no larger than a stock-strock 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?

Giving yourself a challenge, eh?
The CalTrac leafs/bars really don't hurt daily cornering - not an autocross set up - but certainly still a nice driving set up.

I've personally not had good luck with making a fast Q-jet - it can be done of course.
Rev is right about building the entire car to get the e.t. - but if you want corners and economy your tarting to push the reality.
Read of Hand, Butler, Bishop and others - McCarthy, Crocie - the old timers had plenty fast 400 birds.
Talk to Rev about the one he has.....

I doubt I'll ever autocross, just wanted to make sure it didn't interfered with daily driving.

As for economy, here will be my methodology:
With weight and traction considered, I will get the minimum amount of horsepower necessary to be 12.8. I will use the smallest venturis, plenum volume and runner cross-sectional area I can to reach that hp goal. Knowing a ballpark area of hp, I wouldn't want to beaf up the bottom end anymore than I would need to.

Fair enough.
Lose weight, get traction and use the lightest rotating assembly balanced to the hilt.
Pontiacs like small volume intake runners = port velocity at low rpm = torque.
You'd enjoy a 389 tri-power for it's center carb economy and 6 barrel grunt ;)
You could cut a 421 crank to fit the 389 block and nobody would ever know :shock:
Then you could look for 11's :)
Did a motor like this to appear stock in a 66 Goat awhile back
Not a budget build anymore, but sure would be cool!

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 like to put extra whims and stigma on my cars. I think it makes them go faster.:)

If budget was completely not an issue, I always wanted a 4x2bbl delloreto setup with 8 B/A velocity stacks peeking through the hood.

If budget was completely not an issue, I always wanted a 4x2bbl delloreto setup with 8 B/A velocity stacks peeking through the hood.

:cool:

What are you using for your Tranny? If you want performance + fuel mileage nothing will do that for you like a T-56.:D

If you want to use an auto or a 4spd I understand but there is nothing quite like a 0.5:1 6th gear to make those gallons last.

What are you using for your Tranny? If you want performance + fuel mileage nothing will do that for you like a T-56.:D

If you want to use an auto or a 4spd I understand but there is nothing quite like a 0.5:1 6th gear to make those gallons last.

that would be nice behind a Pontiac V8 as they are low rpm torque motors ;)

I haven't seen a T-56 fitted to one yet bu I'm sure it can be done.

You read my mind... in the long run I would love to have a T56 in my car. I want to put a t56 in sooo bad. My understanding of trannies and compatability isn't so great. I know I'd need a BOP-T56 bellhousing like so: http://store.summitracing.com/egnsearch.asp?N=700+4294822099+4294908153+42948401 35+4294925083+115+4294856873
Would I need a custom flywheel? I'd most likely have to fab the tranny tunnel. And fab or buy (I'd rather fab) a crossmember for the conversion. Then fabbing the hydraulic clutch linkage would be a bear right? Feel free to correct me as I have no idea what I am talking about lol.

Ballpark... how much would this cost. I'm pretty sure I currently have a 2sp powerglide: that has to go.

nice find on the bellhousing :thumb:

oh, you're getting into some real dream work now! lol

If you ever get the trans, have cash for that bell, I'm sure a regular clutch will work but try fittinmng all that into a Pontiacs space - MAJOR fabrication.
Cost? no clue. Thousands by the time it bangs gears on the road.
Headers will hit, floor is too small in areas - driveshaft - clutch juice, pedals - all custom.
Look at Hot Rod, Car Craft etc - I'm sure a 67-69 Camaro guy has done it.

nice find on the bellhousing :thumb:

oh, you're getting into some real dream work now! lol

If you ever get the trans, have cash for that bell, I'm sure a regular clutch will work but try fittinmng all that into a Pontiacs space - MAJOR fabrication.
Cost? no clue. Thousands by the time it bangs gears on the road.
Headers will hit, floor is too small in areas - driveshaft - clutch juice, pedals - all custom.
Look at Hot Rod, Car Craft etc - I'm sure a 67-69 Camaro guy has done it.

There have been loads of guys doing the LS1/T56 swap into 1st gen F-bodies. There is a guy who frequents this board who has done it, and I am probably going to be assisting another LS1/T56 transplant in the upcoming months.

So the info is out there, but the cost....:shrug:

There have been loads of guys doing the LS1/T56 swap into 1st gen F-bodies.
So the info is out there, but the cost....:shrug:

Keep in mind though - this guy wants the T-56 behind a Pontiac V8
I haven't seen that.
I'd do a TH400, Gear Vendors overdrive if it were mine :)

Keep in mind though - this guy wants the T-56 behind a Pontiac V8
I haven't seen that.
I'd do a TH400, Gear Vendors overdrive if it were mine :)

No, but that's just an adapter issue, or a bellhousing like the one he found. I believe it's ~$500 to mate a LSx and a Porsche G50, so how much more could it be to mate a Pontiac 400 to a T56?

The main thing is there are a lot of people who have put the T56 in a first gen, so he definately can find help if he needs it.:)

The main thing is there are a lot of people who have put the T56 in a first gen, so he definately can find help if he needs it.:)

Yup - agreed ;)
With all the first gen Camaros I'm sure the basic formula to swap is written in an article somewhere.
Only issue I see are the Pontiac headers fitting around that big bell - otherwise probably like a BB Chevy swap.

Yup - agreed ;)
With all the first gen Camaros I'm sure the basic formula to swap is written in an article somewhere.
Only issue I see are the Pontiac headers fitting around that big bell - otherwise probably like a BB Chevy swap.

Eh, just have the exhaust exit out of the fenders:shrug:

Who need mufflers anyway?:D

Eh, just have the exhaust exit out of the fenders:shrug:

Who need mufflers anyway?:D

:eek:
:confused: why didn't I think of that
"the shortest distance between two points is - funny car headers!"

:D

Well, this is my first automatic car. Which is a huge turn off. Would less fabrication be require if I were to use a T-5? I know the factory T-5's are glass and I believe a TKO is worse option than a boneyard T56, I know TexMoCo offers built T-5's rated for 425 ftlbs for around $1300. Does anyone know of better options, or am I right thinking a t56 is a whole other level when it comes to a tranny.

Well, this is my first automatic car. Which is a huge turn off. Would less fabrication be require if I were to use a T-5? I know the factory T-5's are glass and I believe a TKO is worse option than a boneyard T56, I know TexMoCo offers built T-5's rated for 425 ftlbs for around $1300. Does anyone know of better options, or am I right thinking a t56 is a whole other level when it comes to a tranny.

The T56 is light-years better than a T-5, in my opinion. If you didn't want the hassle of fitting a T-56 then I would say your next best option is a M-22. It's a solid, proven transmission that was offered in first gens and therefore should fit. But then again that doesn't solve your gas mileage problem by only having 4 gears.

I'll look around and see if I can remember the guy who had the LS1/T56 camaro and direct him to this thread to shed some light on the matter.

The T56 is light-years better than a T-5, in my opinion. If you didn't want the hassle of fitting a T-56 then I would say your next best option is a M-22. It's a solid, proven transmission that was offered in first gens and therefore should fit. But then again that doesn't solve your gas mileage problem by only having 4 gears.

I'll look around and see if I can remember the guy who had the LS1/T56 camaro and direct him to this thread to shed some light on the matter.

Said guy has been found!!

I would definitely go with the 6 speed if possible. I ran back and forth from Houston to San Marcos on IH10 for 3 years getting 27 mpg in 6th gear...then dropping down to 3rd or 4th for some fun here or there! It shouldn't be too tough to set up....you just need a TH400 style crossmember, the hydraulics and hardware to set up your clutch pedal and you'll be good to go. I did the whole setup in my driveway. (granted its been a while) The toughest part is adjusting the travel of your clutch pedal to get the master cylinder to (dis)engage the clutch properly. You'll also need an adapter plate on the firewall to get the master cylinder mounted at the right attitude. Theres a couple of guys who sell them, it shouldn't be too tough to find them online. Let me know if you need any specific tips!


edit: I just realized we're talking about a Poncho here (thats what I get for not reading the whole thread)


Im guessing you'll want to seek out an LT1 style T56.....that should require less modification. My assumption is based on the fact there may be more parts available to convert from an SBC setup to a pontiac rather than LS1. Good Luck!

Great to hear from one who has accomplished :thumb:
I bet over on the performanceyears or clasicalpontiac boards if you search or post - you'll find a Pontiac with this done to it.
I know the M-21/22 with a Gear Vendors over/underdrive has been done - that's a neat set up there :)

Of course - this is all theory for now - thread started with our guy looking for first engine building tips - we'll be waiting!

It is true that the thread is wandering, but I'm all over the place too, so I have no problem with it. I'm throwing ideas in every direction: As an issue of time, and experience my teacher who restored a 69' bird in high school took the route of getting a low mileage, some-what stout engine + tranny from a boneyard, and putting bowtie mounts on. That was in 1985 and a 74' chevy was his choice. Few salvage yards in my area seem to care about anyhting before 91' or even 96'. (Shout out: any good boneyards in the Philly area???) Now, as much as I would like to stick with a poncho, factoring time and expense this sounds like a good possibility. My question is, what could be a low-mileage, low-fuss and low-cost (I'm not thining LSx/LTx) swap that could eventually facilitate 12.8s? I was considering an L31, and switch it back to a carb so I wouldn't have to change to a high-pressure set up, even though I saw something about a high pressure mech pump in Hot Rod recently. That was a lot... see, I'm everywhere right now.
Whaddya think?

Any Chevy 350 block is an adequate platform for 12.8's in that weight range. You can pickup a cheap 350 from a Chevy van, truck, camaro, etc. for less than $500 that will run. Later on down the road you can add some Dart Pro 1 heads, a single plane intake, a big nasty bump stick, and you're at your goal.

The best thing about the 350 is it didn't change from the late 60's until 1992 with the introduction of the LT1 (with the exception of making roller cams standard in 1986) so there are a lot of them out there.

It is true that the thread is wandering, but I'm all over the place too, so I have no problem with it. I'm throwing ideas in every direction: As an issue of time, and experience my teacher who restored a 69' bird in high school took the route of getting a low mileage, some-what stout engine + tranny from a boneyard, and putting bowtie mounts on. That was in 1985 and a 74' chevy was his choice. Few salvage yards in my area seem to care about anyhting before 91' or even 96'. (Shout out: any good boneyards in the Philly area???) Now, as much as I would like to stick with a poncho, factoring time and expense this sounds like a good possibility. My question is, what could be a low-mileage, low-fuss and low-cost (I'm not thining LSx/LTx) swap that could eventually facilitate 12.8s? I was considering an L31, and switch it back to a carb so I wouldn't have to change to a high-pressure set up, even though I saw something about a high pressure mech pump in Hot Rod recently. That was a lot... see, I'm everywhere right now.
Whaddya think?

You asked - I think that is lame. Get a Camaro 6 cylinder body and put the 150 zillionth small block in it :(
Leave a Poncho a Poncho.

You had my utmost attention and respect as a newbie wanting to get stout numbers from a Pontiac set up - unconventional even!
Look in racingjunk.com, the local papers, Auto Locator, etc - you'll find a suitable 1st gen small block already built up for a grand or less. Add the required headers/radiator/swap components and you'll have a stale cheeseburger from McDonalds like everyone else.

Sorry - you asked what we thought ;)

chief455 makes a good point. I wouldn't begrudge you dropping in a 350 beater motor until you can afford to build up a Pontiac replacement, but he's right, it's definitely far from original.

it isn't original, it's temporary, in the end I do want a 400 tearing things up, but I do know that I have to be able to see progress to feel motivated about this project. I'd rather have it be a cookie-cutter-mobile than one of the 7 out of 10 project cars that are resold before finished. I'm figuring out what it would take to be a driver, so I can give my current DD a 1993 GP to my bro.

Once again, a source for poncho motors from boneyards around philly? Is it correct I don't want a 400 block after '75 due to some wegiht-reduction program?

Quick q just on design. Why is it easy to get 12.8s outta sbc when most people recommend at least a pontiac 400 (more often a 455). Now is this due to the availability of sbc speed parts compared to ponchos, or that poncho builders have larger engines available so why not use them? Or is the sbc simply better than the poncho?

Quick q just on design. Why is it easy to get 12.8s outta sbc when most people recommend at least a pontiac 400 (more often a 455). Now is this due to the availability of sbc speed parts compared to ponchos, or that poncho builders have larger engines available so why not use them? Or is the sbc simply better than the poncho?

It's easy to get good power out of a Chevy 350 (note I'm not talking about the Pontiac 350 or Olds 350) because there is such a huge aftermarket for it. It is a great platform but as I'm sure you know, heads are what make the power, not the bottom end. Because there is such a huge market for it parts are fairly cheap too. I think that is really what people are saying when they say it's easy to make good power with a chevy 350, they're saying it's cheap.

I think you can run 12.8s with 400hp, and Helen Keller could build a 400hp 350.;)

what is the status. i love ponchos