major,
im not sure about rebuilds, but a new modified 6ve1 is around 3 grand, if i remember right. im thinking i saw rebuilds going for about the same, but my memory is a bit foggy .......not sure if the rebuilds are putting the new "benifits" in the engine or not.
but the new modifieds have better rings in the pistons, and i think a couple of better oiling issues.