I took my original seat bottoms into a foam supplier last spring and had them cut two pieces of high density foam to the same dimensions. I believe the front was 7 1/2" tapering to 4" at the rear. I cut 1/2" plywood as a base for each seat, added the foam then stapled on the covers. They looked pretty good, but I didn't take into consideration the fact that high density foam doesn't compress like springs, so it's a tight squeeze between the steering wheel and seat. This winter I'll remove about 1 1/2 inches of foam, contour the edges and probably add a thin layer of soft foam or batting to the top. In spite of the tight fit I was quite pleased with the feel of the seats and I'm sure the additional changes will make them even better.