Spacers, long bolts and washers are used at locations with more than one belt fastened to the floor. This would be in the two rear locations at the side of the trans hump. It would also be in the front on either side of the trans hump. Short bolts are used where there is only one belt attached.

70 Road Runner 383-4 4 speed FJ5 & black guts
70 Charger R/T 440-4 4 speed FJ5 & white guts