Need cam help for 340 Duster

Heads? What is your performance goal?

A decent set up with stockish J heads is a Comp XE268H or equivalent with an LD340/RPM/AirGap intake with headers. Should be in the 325-340HP range with a good tune up and 9.5:1 static compression.

I like 750 vac sec Holley or a 750 DP the same size, especially if a 4 speed. A 340 with auto will usually like a bit more converter than the stockers provide. A nice 2500-3200 one would work really good.

Figure out what you want to do, know your goal, before buying a bunch of parts that may not work.