I just picked up a 509 400 that was taken out of a van at least 10 years ago because it was burning oil. It will be a spare block but I wanted to make sure it was a good core. I pulled off the heads and there is no ridge at all and quite a bit of crosshatch left in the cylinders. Hard to believe this was a carb'd engine. I have no way of measuring for taper. The only problem is one oil ring broke and left a gouge about 1.5 inches down the bore about 3/8" wide. It would clean up at .030 maybe even .020. Any suggestions on sleeving the one cylinder and saving the block for a overbore down the road? Or just go with the least amount of overbore and have at it? TIA, Steve

 

That's what I'd do. I don't even know if a machine shop would sleeve a 400 since the cylinders are so close together.

 

400's can be sleeved, but I would try to bore it first and see if it cleans up. If it does, then bore the other 7 holes and let it ride. Make sure to mag the block to be sure it isn't cracked and pay close attention to that particular cylinder.