Low po DD, the odds are well in your favor. What Nanket said, more info on the scratch. EDIT with more thought (& rereading your OP) I would NOT rebore it but just rering it with some file fit plasma moly rings with dingleberry honing it with a their 320 grit. I dont think that scratch will be any problem & I would bet my last dollar that you will be fine & end up with more power & plenty of longevity (plus you're gaining almost 40 cubes) & you could spend some of that cash on milling the heads.