The Renix and HO pulley mounting plates are not even close. Look it up. For the 4.0:
87-90, 53002904, BRACKET, Idler Pulley Mounting - w/o Air Conditioning
91-93, 53006551, BRACKET, Idler Pulley Mounting - w/o Air Conditioning
when I swapped engines from my factory 91 block I was able to swap it onto my replacement 88 block...