Wrong timing settings

The pickup is a 1984 W150. Took out the old tired 318 and found a 5.2 magnum from a 1992 dodge van that caught fire. replaced all the gaskets and seals; whole top end was burnt to a crisp, so had to replace intake manifold, distributor, etc... Got an aluminum dual plane intake from Mancini racing that would fit the newer magnum engines (lets u mount a carb on them), edelbrock 650 performer carb, and new distributor. Timing chain and gears were replaced and correctly set on the mark. Using a dual magnetic pickup distributor. Timing was set at 10 degrees with piston on compression stroke, using timing marks on balancer and on timing cover. Checked for gasket air leaks, vacuum leaks, etc... No problems there...Backfires through the carb on quick acceleration; i'm assuming the timing is slightly off, but cant find the timing specs for a 92 around here lol ( Im in BFE LOL). Is it also possible that the cam (oem equipment for 92), originally designed for a fuel injected engine, has the wrong timing and duration for a carbed engine? The rest of the ignition system has been checked and found to be ok (ignition module, pickup units, air gap, ecm, etc.,,). The pickup is a 1984 W150. Took out the old tired 318 and found a 5.2 magnum from a 1992 dodge van that caught fire. replaced all the gaskets and seals; whole top end was burnt to a crisp, so had to replace intake manifold, distributor, etc... Got an aluminum dual plane intake from Mancini racing that would fit the newer magnum engines (lets u mount a carb on them), edelbrock 650 performer carb, and new distributor. Timing chain and gears were replaced and correctly set on the mark. Using a dual magnetic pickup distributor. Timing was set at 10 degrees with piston on compression stroke, using timing marks on balancer and on timing cover. Checked for gasket air leaks, vacuum leaks, etc... No problems there...Backfires through the carb on quick acceleration; i'm assuming the timing is slightly off, but cant find the timing specs for a 92 around here lol ( Im in BFE LOL). Is it also possible that the cam (oem equipment for 92), originally designed for a fuel injected engine, has the wrong timing and duration for a carbed engine? The rest of the ignition system has been checked and found to be ok (ignition module, pickup units, air gap, ecm, etc.,,).