Ok, this is where my ignorance will really shine! 1rst, what would cause a vertical 32th" wide divet the length of the cylinder? was it caused by a stuck/ broken ring gap, or is it a worn sleeve gap from a previous repair? only one cyl. looks like this. Otherwise, I cant tell if there is a sleeve in there. 2nd, top of #1 bore is 4.355, bottom is 4.335 Piston is 4.316 I believe. It's been 14 yrs since I mic'ed the bores. I believe these are averages taken from various sides of the bore. Real question is, whats a deal breaker for rebuilding a thin wall motor home 440? Should I just toss it, or can I re bore it at all? Is it worth sleeving etc?