Well Rhinoriders.com is the club I belong to, certainly not my site, I do have my own though. Mort-Man, not sure about your swop could be a lot easier but the change over year was 1985. I found out about the differences when I bought a buggy style body for my 84 model. Dropped the body on and it only fitted on the 4 corners with gaps all along the rest of it. Then I found out the gear lever surrounds wouldn't fit, then it just kept getting worse. It looks pretty much the same until you start looking hard. The frame on the later SJ chassis is a bit straighter giving a touch more ground clearance. The usual give away between early and late models is the flanges on the props. Early models are square flanges. I think 83 models still had drum brakes.