I can tell you about class 4 for late 70's and early 80's. 1978 I won the championship after some good battles with Glen Emery.1979 I was 2nd. 1980 (with Steve Mizel) we were first. 1983 2nd. 1986 3rd. All I raced until 1990 was jeeps except a couple of times a year I would drive one of Mizel's Bronco's,mostly in Baja but a few in the states. Sorry I can't tell you more but my memory is fading and all of my stuff is packed away.Check with JM Bragg,he was the the king of class 3 with some great battles with Rod Hall .Friend him on F B.I'm sure his wife peggy would know. Try the Randall's out of Arizona.I believe it was Grant Randall that beat me for the championship in 79.Good luck,I applaud your efforts. I should have written a book when my memory was working.