You are also going to have floor clearance problems. Factory 4-Speed trucks had a taller, remove-able floor hump. I've seen some in trucks with the original low floor hump, but it doesn't fit just right. Maybe some will jump in and have some suggestions other than cutting and welding in the correct one.

Bill


'60-'72 Chev/GMC Fan
GMC 9500 Fan
Detroit Diesel Fan