This summer I bought one of these blocks at a swap meet for a very recent price. I found out why. Seems there was a hole in the oil filter cavity next to the water jacket. As it turns out, the casting is very thin in this area, (at least in mine) and couldn't be welded shut. They ended up welding the oil filter feed shut, which will necessitate running a remote filter. Just thought I'd pass this on to anyone thinking of going with one of these pieces. I'd have never seen the hole except that I was radiusing the oil gallery. I'll be posting picks of the build on this thing as a matter of passing interest or revisions and work that yourselves may have to duplicate to run one of these blocks. They're very close to the R3's which will likely need the same revisions.