I've been doing research and I found that:
L6 Chevy Crank pin width = 1.029"
V8 Chevy Crank pin width = 0.94"
So the difference is 0.089"

I'm not sure I understand the problem with the rings. Would the extra motion at the bottom of the crank put more stress on them (cause they'd have to keep the rod straight)? And the extra oil I don't know about either. Is that the result of the extra clearance again? I'm doing a lot of reading and searching online but it's taking time to learn.