Torsion Bar Cross Member Isolate Bolt Torque

[73LemonTwist]

I am installing new isolator bushings on the rear torsion bar cross member of my 1973 road runner. The cross member is held onto the frame using 3/8 x 16 grade 5 bolts. The Chrysler shop manual says to torque these bolts to 75 ft-lbs.

The tables I have found say 31 ft-lbs for a Grade 5 and 44 ft-lbs for a Grade 8.

I found out the hard way, what happens when you try to get one of these bolts to 75... Now in the process of extracting what's left...

Any recommendations what torque to use? Stick to 30 for a Grade 5 bolt?

Thanks...