I bought a used 197? 360 that supposedly came out of a motor home. It is a 2bbl, has no air injection holes in the heads, has a egr,. I opened it up and is is really clean inside. It has been apart before. I have not pulled the heads. I did pull the oil pan as I have to install a car pan. On the crankshaft, after the #2 main, it is stamped R X 3 4 in 3/16-1/4 letters. Any idea what this means? I have always seen 010 or 020 if it was cut. I did notice it has a hv72 tag on the oil pump, so that should be a high vol oil pump. I am planning on pulling the heads, swapping the cam, valve springs, and timing chain and running it.