Just as slow as before mods..

WOW
My best advice to the OP is to find an excellent old school mechanical shop. Even if you have to pay to haul it to them on a flat bed, it's WAY better than casting around here with the depth of the mismatch in parts.. They can go through the car, make the best of what you have and then suggest some alternatives to make it better.

If it goes up for sale somebody savy here is going to pick it up, fix all the little glitches and then put a serious small block in front of that 518 and Dana!