Putting a subcompact suspension like a M-II under a pickup is dumb. The Gremlin system is stronger, but it's obsolete. Gremlin parts are scarce now- - - -what about in another 10 years? I'd suggest using a suspension system from a later model full size or mid-size truck rather than destroying the load carrying capacity of your pickup.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!