Passenger car D 60s have thinner wall tubing than Ford truck D 60s. Floater style Dana axles have very thick wall tubes. All 70s are floaters, so the tubing is very thick. It doesn’t seem to far fetched that a 70 could be 60lbs heavier without axle ends/ brakes.
I have shipped 70 housings via UPS to Dutchman and back, not much heavier than a 60 truck housing. So realistically it is a minor difference between a 70 built for a car...and a truck 60..and way more gear options than a 9"
If the results don't match the theory, change the theory.
