318 into a 340

littleman66 said

i found a bit of information, and you can bore them out but you will have heating problems, but there is a poly 318 engine that is much wider, how would i determine if the engine is a poly 318?

the man that ouns the engine said the 318 had a name for it that he forgot, im guessing it might be the poly?

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You can't bore a 318 to a 340. You should never bore any Mopar more than .020 or.030. You can loose the integraty of the bore. The bore may not stay perfectly round and the rings may not seal good, because the cylinder walls will be too thin. Not to mention other problems. Also, a poly 318 has scalluped shaped valve covers with 2 bolts in the middle. Don't even think about swapping parts between the two. What makes you think that 318 has 2.02 heads? Highly unlikely comming out of what it was in. THUNDERBUMPER