Good point on the gears. Stuffing something like a 4.10 under the van would bump the pulling power significantly assuming yours has the 3.21 or 2.93 rear.
The TBI computer will be your limiting factor. Toss all the related stuff in the recycle bin, build a decent motor, and put the A500 on pressure and vacuum switches to control OD.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind. - Stu Harmon
