Just a quick FWI. C4 and Fiero seats have the same cushion height, width and profile. At 6'2" you will be crouching forward on the seat which puts your knees high and close to the steering wheel.
If you want comfort at your height in a Pantera, you'll need to move the pedals forward and drop the floor pans. That will give you the space needed for seats that will allow you to drive farther that around the corner before your butt falls asleep.
The other option is to pull the seat spacer, pull the seat tracks and mount the seat direct to the floor. It's not a great solution, but will help. If you mount direct, I recommend installing some type of a skid plate in front of the bolts so the heads will not catch anything that might go under the car. If a bolt head catches the right debris, it can rip it right out of the seat.