Is a 305 block and 350 the same?

I came across a 84 chevy truck with a 305 in it and was wondering if i could use the 305 block, bore that out and put 350 heads on it. Are these 2 blocks the same just different bores?


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No dont do that the cylinder walls will be paper thin.

Damn, disregard my earlier post, I haven't had ANY coffee today. I thought you had asked about boring a 305 block out to a 350!!! . Not sure how I got that all screwed up but I'm going to put a pot of java on right now before I get my other foot in my mouth.

Usually .060 is the maximum and after that you start having a need for sonic checking the cylinder walls, or sleeving the bores, or block replacement.

Unless there is a need to keep the block for originality, bore it the bare minimum, or replace it.

I cannot see having a block with no overbore, and taking it up to the maximum on the first try, it equates to a waste of a possible 2 more rebuilds in between being wasted in machining and metal shavings at the shop.

I have a Chevy 350 that has a .020 overbore, because thats what it needed to clean everything up on the first try, if I'm lucky and this thing eventually needs a rebuild I will go for .030 if I can, then I will still have the possibliity of the recommended maximum of .060 for an eventual third rebuild.

If you want more cubes, either go with a larger bore block, or a stroker rotating assembly, they are getting pretty cheap compared to when I first started into hotrodding.

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I can get the truck for a couple hundred bucks, and i wanted mainly for the trans, but was wondering about the engine. thanks

no respectable machinist would bother boring it that much anyway

Boring a 305 to a 350 would require a .264" overbore. A bit much, I would guess.

tom

you think Tom ? LOL

Just a LITTLE bit!

tom

Most everything will interchange between the two except the pistons/rings. Even the crank is the same except for the balance(and hence a different balancer but they to will interchange).
Yes, you can put 350 heads on it but the old ticket used to be to put 305 heads on a 350 as they have smaller compression chambers. As was stated, .060 is the max you can bore one and it will net only little gains in hp(mostly from the increased compression)