I forgot to mention, along with SS springs and pinion snubber, my 65 Falcon had an 8¾ rear end from an early 60s Mopar. It had the tapered axle ends where the brake drums were keyed and held on to the axle by a nut in the center. He said the car would jerk the pinion out of a 9" Ford rear. The 289 small block Ford had Chevy valves turned down to 1.94 intake and 1⅝ exhaust. It also had 1.6 Chevy rocker arms.