OK, DDand Charles, I am fixin to show my stupidity. If I bore a cylinder .100 inches. does that mean "total Diameter enlargment", which would mean .050 reduction of the cylinder wall. If I bore a 3.5 inch cylinder .100 inches, I would wind up with a cylinder diameter of 3.6 inches, and a cylinder wall thickness reduction of .050. assuming I am right so far, If I measure the thickness of my cylinder wall and it is .200 inches, and I bore the cylinder .100 inch I would still have a cylinder wall thickness of .150. is this correct.?

Pat.

Yes, that is correct. I just sonic checked the late model block that I have the other day and many of the walls were up around 0.250 thick. Of course, it only takes one thin wall to ruin your day so you have to look at all of them and then use the thinnest as the constraint on overboring.

Stock SL6 bore is 3.400, bore it .100 and you get 3.500 or 3 1/2 inch bore size. Piston selection is pretty good at that size, lot's to choose from including the 89 mm ones (3.504)

A .100 overbore is .050 off each side of the cylinder....that is, unless you "offset bore" to put more thickness where you need it.
DD