True roller rockers are for the most part not available for these early engines. I beleive Harry Warner of the Wayne 12 port Head fame did not use them or to my knowledge make any of them.
For inlines it took many years for anyone to make them for GMC's which were not as popular but raced more.
The one to talk to in my opinion is Jerry Weight (sp?) with the Wayne Manufacuring Co. With enough interest they may be the ones to do it..
Don Johanson (Howards Cams of old) is currently looking to remake a large amount of roller lifters for the GMC with also fit the Chevrolet engine. He can be contacted thru Chet Herbert in Anaheim Ca. He feels there is a lot of interest and it would better if he knew more were looking to add a roller cam. Hardened cam blanks have always been a problem for folks wanting to do one of these as a racer.
I designed my own for a GMC and I'm sure any good speciality machine shop could do them with a good print and the correct material. However they would be very costly. I was lucky to trade some work for mine. I supplied the tips, adjusters and bearings.
Every so often a set of Barker High lift rockers show up on E-Bay. Thomas also made some magnesium ones. I have 2 sets for a GMC, but none for a Chev..
Good luck contacting these manufacturers and showing interest may help get something done.
