3500 vert would probably use an air gap.
If the convertor was an 8 inch more suited to the track and making best ET, the victor.
Good middle of the road choice, Weiand Excellerator, which was how i went

69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight
418 BPE factory replacement headed stroker, 565 lift solid cam, footbrake street/strip car
Best so far, 10.32 1/4
1.41 best 60 foot
6.56 at 104.17