When did Moline change from a single block in the U to the 2 block engine? Years ago I bought a single block tractor and was told it was a 44 model.. Did the R or Z get made with a single block>. Mu U was supposed to have a LP gas head even tho it burned gas. Was told when I bought it that it tested either 53 or 55 Hp on dyno. It was the row crop with dual front wheels. And it had the Live pto put on. Traded it off back in either 66 or 67. Did not know what a serial number was at that time. And I don't think I ever got a picture of it Had full coverage fenders that came down low enough it had a full platform between the fenders. Never saw anouther tractor set up like that.