Thread: question about 400 small block

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short fill with block rock

Originally Posted by pat mccarthy

short fill with block rock

Pat-that would stabilize the bores at the base for sure.The odd thing about these 400's is some have cooling problems and others don't.We know the bores on them move around quite a bit.Kind of a dumb design that GM created with those steam holes.Leaked down some and got a number of different %'s.We have seen filled blocks with the base is fine and the top was crack(thrust side that is).Really not intended as a hi-pro engine even through a number of guys have used then as such.

Originally Posted by 1gary

Pat-that would stabilize the bores at the base for sure.The odd thing about these 400's is some have cooling problems and others don't.We know the bores on them move around quite a bit.Kind of a dumb design that GM created with those steam holes.Leaked down some and got a number of different %'s.We have seen filled blocks with the base is fine and the top was crack(thrust side that is).Really not intended as a hi-pro engine even through a number of guys have used then as such.

well you can not have every thing now can you ? i know of 400s cracking thru head bolts holes as well on over bores i think it was a 060 over. he could all ways can sonic check it that would help as for heat short fill there maybe some heat soak but most of the heat is two inch s down from the deck better water pump alum heads better cooling all can help .thrust side if weak thin walls .bad rod angle. core shift. is going to help crack ahead of the block rock if heavy side load on bores. its that point its time to use a SHP dart block but he did not ask that

Pat,
Two yrs ago while I was at the Syr,NY Parts Peddler swap meet,I found a number of vendors selling "little M " blocks fully machined ready for assembly for only $1,200 bucks.Man those prices have dropped a ton.Not for nothing.