1973 340 Duster Carb question

There is nothing wrong with the proform you have. Like the others said here, its holley based. The only annoyance you'll have is when its cooler out...no choke. You could always go with a different carb, spread bore, vacuum secondary and a choke same cfm.

Your cam is rated for 2500 - 6000 rpms. Thumper cams sound good. Hydraulic roller. Figure out your compression, my guess 9.5( 0 deck, .039 head gasket and 68 cc head) and what gears you want...call comp up and see what they say. 4 spd will be more forgiving. The spec sheet on the cam said street and strip. Someone built a good motor $$$$. Worst case, you recam the motor. Stay hydraulic roller.

Drive if for a while see what happens. Timing may be advanced for the strip...listen for pings...back it off a little. If its an 8.75 rear end, throw a 3.55 in it. See what happens. Read the spark plugs. Once your drive it for a while and figure out what you dont like about it, post about it and we'll give you ideas. There are alot of knowledgeable people here and alot of opinions. You know what they say about options....there just like rectums....and there are plenty of those around here.