Ok, so here's the information I have been given , for either a 312, or 292 the block numbers are ECZ-6015A or ECZ-6015C. I think I have the one with the C. Now here's what I have been told that indicates a 312, on the crank flang there will either be a indentation with nothing, 292, or a indentation with a bump or something of the sort, 312, right? I am going to try and post a photo that has the indicator, and let me know if I am right.