I have read articles about the competition 371 and my understanding was it had the bumps on the valve covers because it had adjustable valves and was the only Olds engine that did since the 303. It also came with a special cam that was available from the dealership. I have had a hard time finding good info and was wondering if anyone had reliable sources - articles or videos on it. Note that it was a step above the J-2 in performance, according to what I've read. Has anyone here ever owned one?

 

The valve covers you refer to were for the 1957-58 "371" cubic inch engine. The reason for the "bumps" was to make room for adjustable rocker arm valve lash adjusting screws. The reason for the adjustable rocker arms was the solid lifter cams used in stock car racing back in those days. From what I have read and heard from "old timers" the cams were ground by Isky and were about 262 degrees with less than .400" valve lift.

I think the valve covers will work on engines back as far as the 303's. In 1959 Oldsmobile changed the valve cover mounting to bolts around the perimeter, from the two bolt style. The rocker arms were made by Gotha, back in the day, but company is out of business.

Isky was a popular cam grinder "back in the day" and some "Olds guys" liked Engle cams. Isky may still have the specs on the original J-2 cams. There is a small cam grinder that can supply a cam with 265 degrees and .495" valve lift that would work well.

I don't know of any articles or video's of J-2's. I don't know anyone alive who may have had one of the "race" J-2's.