Just as slow as before mods..

Got to be some old school car guys around you. Heck go to a car show and look around.
Just a competent old school guy who can help you cover the basics.
Things like retarded timing and carb not opening all the way can kill performance.
A budget head swap down the road might be a set of magnum heads with a good valve job and resurface.
In the mean time if you can afford it just park it in the garage and cool off for a bit. Hard to make good decisions when you are upset.
Love the car and hope you get it sorted out.
Would love to have that rear end in my duster.