Did a 84 block with 20 head a few years ago. 22r valves in the stock seats, bowl cut, ported and polished. Used the aluminum 22r rockers with the 20r springs. All 20r's I've seen came with heavy steel rockers. Valve float was 8000 with stock cam. Just had to see a couple time. It's helpful to find a 20r head that had a mechanical fuel pump too.
