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Discussion Starter #1
Well I have a 402 out of a 72 chevelle that I was planning on using, but it needs a complete overhaul. Cylinder boring, line bore, possible deck job, New bearings, new pistons, new rings, timing chain, and the list goes on.

I also just got a 455 out of a Pontiac Catalina it needs torn down and the cylinders should hone out. Then put new bearings, rings, freeze plugs, and timing chain in. Also probably get the rotating assembly balanced for performance. Then I would have to do a little mild performance up grade with cam, lifters, valve springs... basically all the little things I would do to the 402 to get it ready to be a hot motor. The basic engine work needed on this 455 is significantly less than the 402.

Now for the opinions (yes I know I'll get personal opinions so no hard feelings will come of them just give it to me straight.)

Which one would you all go with?
Has anyone here fit a Pontiac engine in their third gen Nova?
What type of problems will I have with this conversion if I go this way? (Motor mounts, bell housing, clutch linkage, headers, fire wall clearance...)
Does anyone know how to adapt and overcome these problems?
 

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i agree, sell them and get a 454.
 

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I had a 71 that had pontiac 400 in it and they either didn't care or it didn't fit well, but the fire wall was beat pretty bad.The engine was out when I got the car.Pontic,olds & buick use same style bellhousing.I would stay with 402 or 454 like previous votes.455 have large main journals and don't like hi rpm's (5500)and the heads don't breath well unless you get ram air III or IV heads.Chevy parts are more readly available and cheaper.That's my 2 cents.
 

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Discussion Starter #5
Fatcat said:
I know you ain't gonna like this one, but, I'd sell both of em and find a 454.
Not a question of like or not I asked for an opinion.

That is an option I really didn't think about. From what I've seen though the Potiac 455 are not really selling for much when compared to the BBC's. Also isn't the Pontiac 455 a little smaller than a Chevy 454 in terms of outer dimensions and weight? How hard would it be to adapt it in? I might end up going with an auto if It looks like clutch linkage would be an issue. Also I've heard that the Pontiac design tends to be a bit more torquey than the Chevy design? I know I saw a company that sold conversion motor mounts, I just can't find it again. Also I got the 455 from my cousin for free so I wouldn't feel right about selling it for my personal profit. Worse case I would keep it and jam it into a project later on down the road. Also I think it would make a very interesting conversation piece down the road.
 

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The Pontiac as more torque do to longer stroke,not sure on demensions the heads sit differently so I think it is narrower than Chev BB.Doesn't the Ventura use this set up,I do know pontiac only has one block For 267-455.
 

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I wouldn't presume the 455 only needs a hone. In fact often when you hone you only make OK piston to wall clearance "too much". Anytime you tear down an engine expect surprises. Rebuilding and buying performance parts will be more expensive.
While the swap isn't difficult it may be more expensive than Chevy swap.
I seem to remember 455's being wider at the exhaust than a BBC.
 

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Since your building a hot rod and the price of the 455 is right, I would go for it. You need a transmission or bell housing with a BPO bold pattern. But I wouldn't invest a ton of money in the 455.

Here is a 71 Ventura with a 455.
http://www.cardomain.com/ride/402095
 

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Discussion Starter #10
Well I started doing a little more research on it today. While the Ventura actually used a chevy engine from what I've found, the 67-69 Firebirds did not. As most of you know their front subframe works on our car also. Mounting the engine is only going to cost around $100 for the towers and mounts. After further looking the clutch linkage is all the same so all I need is the bell housing in that department and they go for around $100 also. The engine ran fine when removed a little over a year ago, had a little smoke during start up. So I'm thinking of taking a look at the innards with a machinest and see what we think. Worst case senario I pay the machinest for an hour or two and realize it is not worth it. Best case we can re-ring it and do a light hone and a new beast is born. Looking around I'll have to agree Pontiac engine hop ups are more expensive then Chevy engines. This leads to another question though, if all that is true why are their still fans of the Pontiac engines? While my grandfather was alive he worked at a GM garage and mostly worked on Pontiac, Buick, Oldsmobile, and Cadillac cars since those were the cars the attached dealership sold. While in his off time he was a pit crew chief for a sprint car team. When they first started out they ran SBC 289's since they were cheap, but later he started running the Pontiac engines when the team started to win enough and get enough sponsorship to actually buy things. He would be able to tell me if he was still around, but I don't have that luxury. He might have done the swap due to a new class with new CID rules or something else. The world may never know.
 
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