Good pieces of info thanks. Disappointed about the tuning. Wondering too about the 750 being a better choice although seems like a lot of carb for a basic smog engine. It'd be nice to stay with factory linkages if I can with no or small modification. I'll take a pic of what's there now. As far as I know the only changes are at the carb in which I made and that's a Holley throttle extension lever and the stud for Chryslers. That just made everything work better with the 1406 carb that was on the truck when I got it.

p.s. should I not be trying to fix what's not broken?