well, clearance issues can arise depending on how the 383 is built. Are you using a kit that includes clearanced rods? I'm running a 264 megacam in my 383 and it seems pretty nice. That appears to be a roller cam that you posted. Do you have all the roller equipment? There's other cams too, you might get a list of the stuff that's going in and on the engine (exhaust, compression ratio, rocker ratio, roller vs. flat tappet) and then call some cam companies and tell them the intended application, they should give you something close.