Old trick we used to use back in the sixties is to power time it. Loosen the distributor hold down so the distributor can be moved, but not too easy. Crank the engine and rev it past the mechanical advance limit. Hold the revs and advance the timing by moving the distributor until the engine starts banging. Back the distributor off a tad and lock it down. Take it for a test drive to see if you have any valve clatter, if so back the dist down a bit more.