Slant six timing issues

Its 1970 plymouth valiant has long aussie ram intake manifold, 4bbl QFT carb, msd6al box with blaster coil. distributor was new out of box. Vaccum advance was hooked up when starting but ive made no adjustments with it hooked to the carb. NEW DISTRIBUTOR FOR CHRYSLER DODGE PLYMOUTH 1973-1987 225CID 3.7 STRAIGHT 6-CYL | eBay

That distributor is a genuine Chinese knockoff, and is suspect.
Also make sure the carb secondaries, are not cracked open. Make sure he throttle linkage in not holding the carb slightly open.