[ponyakr]

The guy that bought one of my 455 engines is trying to make it work in a Sunbird. Does anybody here have actual experience putting a Pontiac V8 into a Sunbird, successfully ?

Will any off-the-shelf 4-tube headers work, without any tube mods/re-routing ?

How about 3-tubes ?

Shorties ?

RA manifolds ?

I know Don Kennedy has a 9-sec SS Sunbird with the alum head 428. But I figure he has custom headers.

[PDC]

455 in a Sunbird sounds dangerous.

[goatless]

As was mentioned on one of the FB posts about the car, log manifolds would probably be the easiest thing to fit on there. With a little bit of effort they can actually be made to flow ok. Jay Delaigle had a full weight '74 TA in the 10s with a heavily modified logs. My own '69 Lemans convertible goes mid 12s with a lower effort set of logs... at a race weight well over 4000 lbs. I've got to imagine that Sunbird weighs a whole lot less! How fast is he looking to go?

[Sirrotica]

A friend of mine did a SBC into a Vega chassis, same as a Sunbird (race car, not street car) and had tons of trouble twisting up the chassis from the firewall forward even with a cage in it. Those front ends spread even in a stock daily driver car with a stock engine in it. I'd wager he's going to have trouble with a 455 over the front wheels.

No idea whatsoever what type of exhaust will fit because he's in largely uncharted waters. He's going to have to get the engine in and see what fits it, if anything.

[steve25]

X2 with the Above!
You don't see hardly any of those conversions any more even with small torque output motors because of how they twist up !
You need to add 200 lbs of steel to them just about to not have that take place.

[Skip Fix]

Check with Lynn McCarty they have a SS car Sunbird I believe.

[ponyakr]

Originally Posted by Skip Fix

Check with Lynn McCarty they have a SS car Sunbird I believe.

OK, I've already told him that Don Kennedy has one, & posted a link to his FB page. I'll do the same for Lynn's page.

I'll mention what has been said here about the twisting.

Thanks all !

[ponyakr]

"...they have a SS car Sunbird I believe."

Just looked up a couple of Lynn McCarty cars. One is a Bird. One appears to be a late GTO maybe. Not really up on the late model stuff. Do they have 3 GT SS cars ?

What body type is this ?

[ponyakr]

I think I may have the Sunbird mixed up with the Sunfire.

Is this Don Kennedy car a Sunfire, or what ?

[oldblueponcho]

Originally Posted by ponyakr

I think I may have the Sunbird mixed up with the Sunfire.

Is this Don Kennedy car a Sunfire, or what ?

Yep that's a Sunfire. Going by the headlights and grille, it's an 04 or 05.

[hojs69]

Marion Stephenson's 1990 Pontiac Sunbird; NHRA Fourwide Nationals 2014.

[Skip Fix]

Lynn actually had theirs for sale as a roller a few years ago. His brother I think kept it. Not sure it is actually racing now.

[ponyakr]

Originally Posted by hojs69

Marion Stephenson's 1990 Pontiac Sunbird; NHRA Fourwide Nationals 2014.

Anybody know if it had Pontiac power ?

I think this guy has a 1st gen Sunbird, a 1980 maybe ? Would the front subframe/ engine compartment be completely different than a '90 model, and maybe more like the Astre/Vega ?

[Formulajones]

Are you talking about the first generation 76-80 sunbird that was based off the Vega platform?

I had several V8 Monza's and Vega's that I daily drove as well as raced in UMTR. I ran either 355's or a 406 sbc. Pretty much stock appearing street cars. Never had any twisting or chassis issues with any of mine. Always had the engines mounted solid though.

All the stuff is out there and factory engineered to drop SBC's in these things. I still have 2 complete setups here. Pontiac is a different story. Even GM put the 305 sbc in the sunbirds in 78-79 and had a Formula option.

They never saw the Pontiac V8 but a very cool idea. Going to have to fab your own mounts. I wouldn't even try headers, that would just be a nightmare. Even headers from both Hooker and Don Hardy that were made for these cars with SBC's were a pain in the a$$ to deal with Especially when you have power brakes and power steering like mine did. You could try RA manifolds but if it were me doing the conversion I'd go straight for a set of logs and call it done. They have the best chance of fitting the engine bay.

Now a much easier route, if you want to take off the front chassis from the firewall forward, Jegs makes a tube chassis kit that bolts on the front of the Vega/Monza and would also work on the Sunbird. Comes with more modern control arm setup (factory stuff sucked with little adjustment using dial-a-shims for caster/camber) and 5 lug conversion etc...and the tubular frame makes putting pretty much any engine in there a breeze, even a BBC. Then you can run pretty much any header you want. If I were serious about using headers and making a full tilt effort, I'd be doing the Jegs front clip.

[ponyakr]

Thanks for that info !

Pretty sure this guy can't spend that much on this car.

I suppose if it were mine, I'd try some 3-tubes 1st. They seem to fit most everything else. Also wondering about the Hedman shorties.

Some FB guys recommended logs with center dumps. So, what Pontiacs came with those ? One guy said he used some that fit, in a '77 Astre. Said 1st gen Bird & '65-'70 big car left side logs are center dump.

Just checked the thread. Owner said he tried some RA manifolds, which would not work. Said he has some rear dump logs that'll work. So, that's what he's gonna use, for now.

Hey, it'll still have near 400hp & 500 torque. Should make a pretty spunky ride. Ran 7.30's 1/8 mile, in my '74 Ventura.

[Sirrotica]

There's a reason the chassis companies built a front stub for these cars, it's because the laminated sheetmetal chassis rails bent even with a stock engine and suspension on daily drivers. I've seen plenty of them that couldn't be aligned without being pulled back together on a frame machine.

My buddy's vega race car would bend the front end almost every time he pulled the front wheels and came back down, he was always trying to fix it and strengthen the front clip.

Quote from GM H body forums about the front crossmember sagging with a stock 4 banger aluminum engine:

Man Greg is a warehouse of info.

All I can remember is even with the 4 banger over time the front cross member would sag down and get bad enough to where the front would no longer be able to be put in alignment w/o bending it back. I would add to that area for sure after getting it square.

I would lean toward separating as much as possible, checking all sections and going to a good cage with front and rear hoops. Criss cross the back hoop main bars and weld them together. Mel

It's a real problem, not sure how you avoided it.

[Formulajones]

Originally Posted by Sirrotica

There's a reason the chassis companies built a front stub for these cars, it's because the laminated sheetmetal chassis rails bent even with a stock engine and suspension on daily drivers. I've seen plenty of them that couldn't be aligned without being pulled back together on a frame machine.

My buddy's vega race car would bend the front end almost every time he pulled the front wheels and came back down, he was always trying to fix it and strengthen the front clip.

Quote from GM H body forums about the front crossmember sagging with a stock 4 banger aluminum engine:



It's a real problem, not sure how you avoided it.

It's why I mounted all my V8's with solid mounts, it keeps this from happening. I literally had about 8 of these cars and never an issue with any of them.

I'm not so sure that's the whole reason why the front tubular clip was invented though. These cars were hugely popular in the 70's, Don Hardy and Don Yenko doing conversions with them, Grumpy tearing up the Super Stock classes with them etc.... The tubular front ends made it simple to swap any engine you wanted into these things and gave you more options. It didn't do a whole lot for chassis rigidity, the darn thing just bolted to the firewall LOL Was made so anyone that could measure and use a plumb bob could do it in their own backyard.

[Formulajones]

Originally Posted by ponyakr

Thanks for that info !

Pretty sure this guy can't spend that much on this car.

I suppose if it were mine, I'd try some 3-tubes 1st. They seem to fit most everything else. Also wondering about the Hedman shorties.

Some FB guys recommended logs with center dumps. So, what Pontiacs came with those ? One guy said he used some that fit, in a '77 Astre. Said 1st gen Bird & '65-'70 big car left side logs are center dump.

Just checked the thread. Owner said he tried some RA manifolds, which would not work. Said he has some rear dump logs that'll work. So, that's what he's gonna use, for now.

Hey, it'll still have near 400hp & 500 torque. Should make a pretty spunky ride. Ran 7.30's 1/8 mile, in my '74 Ventura.

Yep I figured the stock logs would work and that would have been my first go to setup. It's all you'll need in these little cars. When I was running a mild 406 in them, with 3.23's out back, it was my daily driver. It was a solid 400hp engine and similar torque. The car flat boogied and on the street was a terror. 26-2800 lbs. doesn't take much power to run 11's and will do so on rock stock street tires, even with large amounts of tire spin Very fun way to go fast for not much money.

[Sirrotica]

Discussion on H body forum, subject is frame spread and ways to band aid It, including solid motor mounts, (SBC, not a Pontiac of course) motor plates, etc.

http://forums.h-body.org/viewtopic.p...33810&start=15

The front structure was just about strong enough from the factory but not quite strong enough. If you add in a car that is rusty (not an Arizona car) . Then the added weight of a Pontiac V8 over anything GM put in them.

BTW, my buddy definitely had solid mounts in his SBC Vega race car, plus a cage and he regularly bent the front stub. Always ended up with too much negative camber, then back on the frame machine to bend it back again.

My own 76 Sunbird (231 buick V6) also had too much negative camber and couldn't be aligned, ended up trading it rather than fixing it, PA car with rust issues.

Just my personal experience with H body street and race cars, not going to belabor the point any more. I just wanted the OP to be aware of the shortcomings of the stock front stub.

[Formulajones]

I don't think the front motor plates are that effective at this type of issue because all the ones I've seen mount too high to the inner fender structure. The problem lies at the bottom.

Simply put, these cars don't have cross members, and the suspension mounted to the inner fenders does pose an issue. No arguing that. The solution needs to be at the bottom of the structure. Hence the reason I ran solid mounts, basically using the engine block as a structural support at the lower portion of the fenders where they tend to spread.

This method never posed any more issues for me with the negative camber problem with iron V8's between the rails and daily driving them for years as well as competing and abusing them in UMTR with a stick behind it. There is no way for it to move any further unless the block split in half. If the problem is still showing itself for others, I can't help but think they have another underlying issue at fault.