I have a used engine that came in my formula that had a Jasper tag on it. It is bored 0.040 over on the cylinders.
Casting number is 14010299 and it is a pretty generic 2 bolt main - 2 piece rear main seal motor. Late 80's GM truck motor stock with stock mercruiser internals, tappet cam for a whopping 260 rated HP.

Is there any concern on the cylinder wall thickness with a +.040 bore on a sbc like this to run it as is?

Brian

Normally I would say not too big of an issue at all , but if it's been in the boat a while (with raw water cooling) I would have to wonder how much deterioration is on the outside of the cylinders in the water jackets making them even more thin.

I have a couple of 40 over 357's. I would not bore any raw water block. If it needs machine work, spend a buck or two for a pass car-truck core that spent it's life full of anti freeze.

No no, I am not boring it further or looking to rebuild it. It came out of my boat and was a replacement motor from jasper, looks pretty new. Someone is interested in it as a stock replacement for one of their motors until they build a new set of higher hp motors. Just some concern over it being 40 over.