Probably a Mustang II aftermarket front suspension with tubular control arms, either conventional coil springs or coilovers. Front track width will increase from approximately 52.5" to 56.5" or 58" depending on choice of rotors. I will move the front axle position forward 2" to 4".

The rear will be a trailing arm with coil springs or coilovers and a panhard bar same as stock just beefier.

I may use a Chevy S-10 truck rear axle, the track width will increase from approximately 52.5" to 54". I will use deep reversed rims to match the front track and allow for bigger tires on rear.

For the engine I am considering a V6 over a V8 since the V6 will be about 4" shorter and not intrude into foot room as much.

Maybe an automatic overdrive transmission since the shifter location on a modern manual 5 speed may not be in the most comfortable position.

All of this will be sitting on a 2" x 3" x 1/8" wall steel tubing frame that I will build.