ill check base timing. it should be checked with vacuum advance unhooked, correct? as for which cam not totally sure i have a feeling it is 284 /284 lift - 484 /484 duration
any way of knowing without tearing down engine?
If it's a 284/484 make that about 18-22* initial as long as it doesn't kick back on the starter when hot. You could try putting a dial indicator on the retainer and measuring lift. It won't be entirely accurate with the crappy valvetrain angles in a SB. Give you an idea of which cam it may be.
You'll probably be in the distributor to limit advance so your total is OK.
