Too many variables to just guess. A 284-.484 probably would work. but have the heads or block been cut? What about head gasket, how thick? Installing it straight up or advancing or retarding it? Big valves or standard? How good are the valve springs? How high you gonna rev it? WAY to many variables. Put some light checking springs on #1 with a dial indicator and see how much room you have now to make an educated guess. Unfortunately, you can't know for sure until you put the cam in the motor.You need at least .090.