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
Best so far, 10.40 @127 1/4
1.41 best 60 foot
6.60 at 103.90 1/8