455 Changeover

D94

D94

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Hello all.

I have a question regarding my 1973 Firebird restoration. I had a 455 built about 20 years ago when I first got this car. Long story short, at some point I discovered a hairline crack in the #1 cylinder. Since then, the car sat in a garage until last summer. I want to know if I could get a 455 block and have it machined .30 over like the block I have now, and just swap everything over to the new one. I would do it myself except for the block to keep cost down. Is this possible to do successfully? Any info would be great. Thx.
 
Why wouldnt you be able to do that, am I missing the point of your question?
 
Whenever I mention it someone, I always get a response about piston ring tolerances, or having to maybe redo the crank or something with the heads. It just seems logical to do I just don't want to miss something. I want to keeo it simple, should be a no brainer if I can find I block.
 
Sorry ,you are right, everything will have to checked like you are starting over , you can do it yourself with plasticguage and a feeler guage.

Not too difficult, but tedious and time consuming.

Doug in P.R.:cool:
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Correct, no two engines will have the exact same tolerances, you have to measure everything.
 
Even though you will have to check all the tolerances and maybe even take a crank and block to a machine shop, It is still the best option. even If you had new parts, you would still have to do that because your using a used block. Tolerances change and very when using used equipment. your best bet is to take your block and crank along with main caps to the machine shop and ask them to check your clearances. they can tell you if you need to use oversized bearings or have a crank turned and mill the mains. If you are going to have the block bored anyways, thats the best solution. I'm also assuming you are going to use a rebuild kit. If so, oversized parts can easily be selected in a kit and for a decent price, you can even get pistons included. If you use a machine shop and buy a rebuild kit, the pain won't be nearly as bad as many are making out to be. But like I said, A rebuild kit is a must. a machine shop is a must. Another benefit of a machine shop is they can check for cracks and defects that the eye can't see. It would be a bigger waste of time to rebuild a motor and then find it also had a crack. I hope this helps
 
Yes, it does help, and thx for all the advice guys.

First thing I need to do is find a block, not having any luck so far... Second find a good machine shop by me in Northern NJ. Not much luck yet there either.

We'll see....
 
See if there are any local Pontiac, Chevy, etc. car clubs I'm sure they could recommend a machine shop.
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Dont lose sleep over this cause I've been through it and it was a piece of cake.........................Motor was even faster at the track after the swap of parts.

The other poster is right about getting the block checked for cracks ( magnafluxing) and maybe install new cam bearings. ( if you dont personally know the block's history) or the crank or cylinders dont measure out.

Unless you buy a running engine like I did...........you might save yourself some $$$$ and not pay a shop that much.

Doug in P.R.:cool:
 
D94 said:
Hello all.

I have a question regarding my 1973 Firebird restoration. I had a 455 built about 20 years ago when I first got this car. Long story short, at some point I discovered a hairline crack in the #1 cylinder. Since then, the car sat in a garage until last summer. I want to know if I could get a 455 block and have it machined .30 over like the block I have now, and just swap everything over to the new one. I would do it myself except for the block to keep cost down. Is this possible to do successfully? Any info would be great. Thx.
Click to expand...

Have you thought about a cylinder sleeve?

Doug in P.R.:cool:
 
92 Sunbird LE said:
Have you thought about a cylinder sleeve?

Doug in P.R.:cool:
Click to expand...

sleeve should be pressed in befor motor is bored. it will distort the cylinder(s) next to it!

you can use a 400 block and have your mains turned down to 3" on the 455 crank.

i can't believe the mashine shop did not check the block for cracks first!!
 
Last edited:
Question: Can a 455 .030 block with a crack in it be sleeved?

Return Email from Butler Performance:

"Yes, we sleeve Pontiac blocks regularly and if done correctly may end up being the strongest cylinder in the block.



You just want to be sure the crack doesn’t run all the way up to the deck or down into the main area."




Butler Performance
2336 Hwy. 43 S.
Leoma, TN 38468
Toll Free # 866-762-7527

Email: info@butlerperformance.com
www.butlerperformance.com

Doug in P.R.:cool:
 
First off let me say thanks to everyone for their input and advice, you guys rock!!

I just got off the phone with proformance unlimited who is not to far from me ( about 70 miles) and he said he could sleeve it with no problem. The guy I spoke to was very cool, and the price he quoted me was awesome I think. Compared to what I was going to do.

One thing I forgot to ask , maybe you know, when I bring the block down do I just bring the bare block ? Have to find out. I'm pretty new to this.

Thanks again everyone I'll keep you posted.
 
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