Linkage set up on 1974 Plymouth duster with 318 automatic
What did you use for throttle/kickdown linkage? *Looks* like stock 2 bbl. stuff to me offhand... that needs some mods to make it work right. The kickdown looks like it's waaay off.
@318willrun has some videos on the subject, as well as many threads on here- try these for starters:
318 4bbl upgrade. Help
1973 360 upgrades
MoparGal (Alexis B’s) 1975 Plymouth Duster Build
Do a search and you will find many more.
You need to get that sorted before you put any miles on it.