Right now I have an OHC engine in the car, so I can't measure for V-8 distributor clearance! And PLT1 brings up another possible variable, difference in the compression or position of the various mounts.

Tom, is there somewhere that I can access those numbers on the net?

CDjr, so does that mean a total max difference of 1 inch between possible fore/aft locations?

Thanks, Jim, that's a good start! Vikki's numbers indicated that one of her cars' subframes could be shifted rearwards by the amount that CDjr stated.

Had I known that there would be that much difference in the cars as they came off the assembly line, I would have loosened my subframe and shuffled it back to give the least amount of clearance possible before starting fabrication!