It sounds like the truck it came from had the engine/transmission mounted tail-low. Some hi-perf guys will mount their rears a little 'down' from parallel with the trans so that they will get closer to parallel when high torque is applied to the rear and the axle twists slightly upwards. probably best in the long run to re-do the perches so the rear matches the rest of the driveline. Your u-joints will thank you and last much longer.
Current fleet (subject to change w/o notice) \'49 GMC 3/4-Ton , 60 Austin Healey Frog-eye Sprite (some assembly required), 2011 Dodge Avenger, 2015 Jeep Cherokee. No, they don't all run. My other ride is a (B737)no, (B767)no, A320.... Update... was Embraer E190, now Boeing B787. Knowledge is a wonderful thing, but ignorance means you don't know you can't do something.
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