In mid 60's, little brother built a 364 (4 x 3 5/8)in from my spare 57 block using a welded stroker crank and Jahns pistons.
We hit a sand flaw low in 1 cylinder but because it was below ring travel we accepted it as was.
The 58 vette it was/is in stayed around and when he did a more restoration in 99 we stripped and freshened up the engine and installed sleeve in that hole.The sleeve required an additional overbore of .187 and the cylinders were already .125 over so a total overbore of .312 and the cylinder we sleeved just barely broke through in 1 place.
The trouble with big overbores is you never can count on the cyl wall being sound or well centered with the original bore centers.
That being said before the cheap 327 short blocks became available, a lot of "4 inchers" were created around here and I don't ever remember anyone having trouble with thin walls.
We couldn't believe it when the word on the new 327's was don't rebore beyond .030.
I was boring a 327 of the "right numbers" .030 for a friends 66 vette in about 95 and when we hit sand holes in the 3 rd cyl I told him to give this one away and lets start over.
I recently sleeved 2 cylinders in a 50 Studebaker champion that had been parked since 1955 had 26,000 miles on it and these 2 cyls had sand holes that had leaked since new but had sealed off of their own.
There can be a lot of surprises when you start boring Detroit iron.
But then that Stude wasn't Detroit was it?
