Crane has aluminum roller/rockers for the 250/292 and Crower has them in steel and I think those will fit under the stock cover. You'll probably want to consider hardened exhaust seats, because of the unleaded gas. You may want to do a little reading about this engine and this book by Leo Santucci has some good info.
[img]http://www.inliners.org/merchandise/images/chev_ex_small.jpg[/img]


'67 GMC 3/4 292 4spd