Pontiac V8 H-Body

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Pontiac V8 H-Body

Postby res0o7eb » Fri Jul 07, 2006 11:57 pm

Has anybody put a Pontiac V-8 into an H-body?
Is it possible to fit one between the stock frame rails?
With minimal cutting or 'persuading' the sheet metal with a BFH?
Pontiac heads are vastly different than Chevy heads. Would stock exhaust manifolds clear?


EDIT(4/4/2007): This is the place for all information about a Pontiac V-8 swap - whether it's a 265, a 455, a stroker or something in-between - into your H-body.
Please feel free to post your ideas, questions, concerns, and pictures here.

I'll try to update this first post with an index or something that lists what is contained in this thread and what information is still needed to do a successful Pontiac V-8 swap.

EDIT(9/17/2007): I hope to have some answers to those first 4 questions above that I originally asked over a year ago.
In the meantime, as mentioned over 5 months ago, I've added an ...
--------------- INDEX -------------------------------------------
0. 301 V-8
A. Lot's of posts here on the 301 just because there really isn't much info elsewhere on the web due to the shunned status of the 265/301 in the general Pontiac community. Also try http://www.301garage.com
B. 301 is a lightweight alternative - both in pounds 8) and power :wink: - for a street-driven Astre or Sunbird.
C. I obtained a 1981 301 for $30 in 2006 and another 1980 301 FREE in 2007. I gave the young kid an extra $20 for helping me load the first one into my blazer. So, two complete boat anchors for $50.
Obtained a complete 1970 354 (350) for $100.
D. 301 Stoker - 301 block with a 326-400 crankshaft (3.00" dia. mains) for a 377 cu. in. engine (4.00 Bore x 3.75 Stroke).
NOTE: Included specs of a 301 stoker in a 1994 Firebird from an article in the May 2007 issue of High Performance Pontiac - 359 cu. in. and 300 RWHP!
E. Most information here will be about INSTALLATION and that definitely applies to ANY Pontiac V-8.

1. Engine sizes, dimensions, and weights.
2. Cooling.
A. Radiator mounted in front of core support.
B. Links provided to other threads in H-body.org.
3. Transmission.
A. Buick V-6 bellhousing bolts to a Pontiac V-8.
4. Motor mounts and frame plates. :idea:
A. Will Buick V-6 Frame plates work?
B. Proper alignment of the engine in the H-body chassis (link)
5. Steering. :idea:
6. Exhaust system. :idea:
A. Minor exhaust manifold interference with 11X heads on the 301 block.
Last edited by res0o7eb on Sun Jan 17, 2010 11:01 pm, edited 25 times in total.
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Postby barebonesracecars » Sat Jul 08, 2006 10:08 pm

I've never heard of anyone on here trying that swap, but I considered it once, about 20 years ago (had a nice 421 Tri-Power!). I would have made a mess of things back then, I'm sure.

Two problems come to mind right off, and you already mentioned one of them: exhaust manifolds and weight.

For the first problem, many guys have built u-jointed steering shafts for big block cars and R&P steering set-ups, so that could be overcome. If you want headers, try to find a very patient fabricator!


Weight: may only be a big problem if you care about handling on curves. You'll also have to compensate with springs, touch-up all the factory welds up front, and deal with more negative camber.

A stock Buick 231 bell housing will work, but finding a 153-tooth Pontiac flywheel might be difficult. There may very well be such a thing, however. I'm not sure. Any B-O-P automatic will of course fit.

Custom motor mounts....

Radiator clearance and cooling issues (definitely 'Griffin' time!)....


If I had an Astre, I guarantee I'd have a Pontiac engine in it.....I'm a Pontiac guy first and foremost! I would probably save up some bread and spring for the Indian Adventures aluminum block and Edelbrock or Wenzler heads, just to get the weigh down to an acceptable level.

Keep us up to date on this....I'm really interested in what you do with it. What type of car are you thinking of using?
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Pontiac V-8 in a Pontiac Astre

Postby res0o7eb » Sun Jul 09, 2006 10:55 pm

Reid,

Thanks for the tips. I thought a Pontiac V-8 was a little lighter than a Big Block Chev. Still, you're right weight is an issue if one wants to turn corners.

I'd put a Pontiac V-8 in my '75 Astre. It currently has a really bad installation of a Buick Odd-Fire V-6 in it. Wires everywhere. Electric fan with switch (no relay) laying on the transmission hump - don't forget to turn it on. Radiator attached with tie-straps. I'll have to take some pictures of the engine compartment for you guys - you'll get a real laugh out of it. I don't take the 'credit' for it, but I wouldn't have done it if I couldn't do it right.

Yes, I'm a Pontiac fan, too. I have an all-original 1969 Firebird Sprint and a 1967 LeMans 'parts car' that I'll put back on the road someday. These are both 6-cylinder cars, though. The Pontiac OHC-6 is a cool engine - for a 6 cylinder. I see you've got a Grand Prix. Gotta luv those early ones - nice lines and they all came nicely equipped.

I had fun driving the Astre today. But, with the Astre being my only roadworthy H-body, I'm hesitant to do anything. Then again, it is beginning to deteriorate. It certainly needs new paint in addition to everything else. As a relatively rare car, I think I'll definitely put it in the garage this fall.

I could use my 76 Vega as a test mule to verify fit of the Pontiac V-8 and determine what needs to be done. I think there are some differences between the 75 and 76 chassis, though.

Oh, yeah, the aluminum IA block would be ideal, weightwise. I don't need the insane horsepower, though. But the rest of the car will have to be looking real good before I would commit to it. Hopefully, by that time the price will be a little lower.

Then again, this is about doing something a little different. I think I'll look for a cheap Pontiac engine around here real soon. I'll keep you guys posted.
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Postby barebonesracecars » Mon Jul 10, 2006 9:17 am

Chevy Big Block: 30.50" front of fan pulley to rear of block; 27.00" overall width; approx. 680 lbs

Pontiac: 29.5" and 27", respectively; approx. 650 lbs

Almost the same. See what the BBC guys do to them to make this work.

I'm not sure I'm going to keep this GP. I bought it because it's 99% rust free and 'relatively' easily restorable. I really want a '62 Catalina, though.
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Would This Look Good?

Postby res0o7eb » Wed Jul 12, 2006 8:21 pm

What ya think? Would something like this look good in the Astre? Carbs would probably stick up through the hood.
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Postby barebonesracecars » Wed Jul 12, 2006 8:50 pm

I'm not sure about hood clearance on the early H-bodies (your Astre), but you might be surprised on a later one. I had more clearance with my air cleaner than I figured. You're probably right, though.

I wonder how a modified T/A shaker scoop would look? Two of them grafted together, just long enough to clear all three cars, and still be mounted to the engine (like stock)?

It would definitely be one-of-a-kind.
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Postby VegaRon72 » Sun Jul 23, 2006 1:27 am

I got to say I love those Poncho Shaker Hood Scoops!! But I have had too many problems with converting my Vega, and there is a lot of parts out there on the market for it. Seems as though it'd be twice as hard to put that Pontiac motor in there. Do they make many parts for that conversion?

Ron
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Postby barebonesracecars » Sun Jul 23, 2006 8:39 am

None. You get the honor of making them all yourself. :lol:
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1981 Pontiac Firebird 301

Postby res0o7eb » Sun Jul 23, 2006 1:05 pm

I found a complete Pontiac 301 engine from a 1981 Firebird for $30.00. Yeah, not my first choice either, but the price is right for what may be more useful as a boat anchor. Pictures posted in my 75 Astre garage.

It's heavy, but 'supposedly' 120 pounds lighter than any earlier Pontiac V-8. Less performance potential, but that's not the goal right now. I believe the dimensions are the same, though. The intake ports on the heads are different, but I think the exhaust ports are the same as any D-port head.

The distance from the front of the block to the water pump pulley mount looks to be an issue. I'll take some measurements, but obviously, the fan will have to go. I've got a Chevrolet 305 engine that I can use as a reference and side-by-side comparison.

No kits available. But, I've seen SBC Vega conversions done without a kit - motor mounts were fabricated. LS1 into H-Body has been done, also. No kit there either.
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Postby barebonesracecars » Sun Jul 23, 2006 1:12 pm

I don't know the exact weight, but a 301 is a bit lighter because there is less iron in the block; hence, less strong. I believe the earlier heads will physically interchange, but the intakes are different since the 'V' of the block is narrower. That's an issue you would still have to look at for steering clearance, etc. if you decide to swap a 400 or something in later.

Not alot of performance parts out there for them...probably none. Maybe find a factory turbo setup from one of them and use it.

Still, it would have more torque than a comparable (stock) 305.
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Postby res0o7eb » Tue Jul 25, 2006 12:35 am

barebonesracecars wrote:I believe the earlier heads will physically interchange, but the intakes are different since the 'V' of the block is narrower.


I think you are referring to the deck height being shorter? Could be. The 301 heads look to be physically shorter as well. The intake ports are siamesed together and not very tall. The intake manifold is very flat. Maybe I'll look for some cheap heads and manifold on craigslist and see if it works.

(edited 8/28/2007) Deck Height:
265/301 = 9.153
All other Pontiac V-8 = 10.23 (or 10.25)
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Postby res0o7eb » Tue Jul 25, 2006 12:50 am

barebonesracecars wrote:Not alot of performance parts out there for them...probably none. Maybe find a factory turbo setup from one of them and use it.

Still, it would have more torque than a comparable (stock) 305.


Cams are available. Heads may interchange, so intake would be available(EDIT - no way!!), too. Don't know about higher compression pistons.

Stock specs show the 301 with 130 smog-infested HP in a 1981 Firebird. About the same as a 305 Monza.

I 'de-smogged' the engine. Whaddya think? A few more horses?
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Postby barebonesracecars » Tue Jul 25, 2006 9:02 am

Yes, the deck height is shorter...the exact description escaped me at the time. Because of that, no other intake will fit. Yes, cams from other Pontiacs will work, but with the poor intake, you won't gain much.

I've never seen any point in trying to do anything with a 301 in any case, unless you had a Turbo T/A and wanted to keep it that way. I would still recommend trying to shoehorn in a 400 (or equivalent), or forget it. It can be done, as long as curve-handling isn't your priority.
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Postby EagleFish » Fri Sep 29, 2006 11:21 pm

Tom,

I had two 1968 Firebird OHC-6s. Talk about a smooooth reving engine. One was a convertible 4-speed Sprint and the other was a hardtop auto. I salvaged the Sprint convertible from a field. The hood was off and the engine was on the ground. A tree had grown up through the engine bay. Had to remove the tree first. Sure wish I had them back. I don't have any pics, either. I really enjoyed them, though.

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Postby cjbiagi » Sat Sep 30, 2006 8:39 am

I believe all Pontiac blocks are the same physical size, there are no "big" blocks or "smallblock" Pontiacs. So why not use the bigger versions?
Clyde.........75 Monza 2+2
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