Senior Tech Team
Join Date: Aug 2002
Location: Gold Canyon, AZ
Re: SBC block bore and taper query ??
You are correct, the tops of the cylinders should have been chamfered after being bored, especially if the decks were surfaced. Your measurements are all over the board and don't make much sense to me. When a cylinder develops a taper shape, the bore is always larger at the top than at the bottom. This is due to the fact that there is much more heat and significantly less lubrication at the tops of the cylinders, when the engine is running.
Your machinist is not totally correct in his assertion that a hone would not correct a very minor taper. A rigid head honing machine, such as a Sunnen CK-10 will indeed straighten a tapered bore.
64 Chevelle Malibu Sport Coupe (original owner) car now has 427" BB, Jerico 5-spd. trans., Dana 60 rear end.
SAE Member (25+ years)
ASE Master Certified Engine Machinist
AERA Certified Professional Engine Machinist