Being 6'4" tall, and having driven Mustangs before , I knew that I would need more head and leg room in my 68 FB. I followed the basic outline from the Mustang Plus article in their catalog and lowered the platforms 1 1/2 inches. Then I moved them back 2 inches. I put the seats in (69 Mach Buckets) and man oh man! What a difference!. Moving them back forced me to weld up the holes in the floor and cut new ones in. Total time... remember, I was using new ones and this did not include cutting out the old ones, about 3 hours. Well worth it to me.