Did they make 5x4” axles for 8 3/4 rear ends?

I dunno. It may be someone who does big work and this one caught him off guard. To be honest most people I know outside of the Mopar world won't have a clue about the SBP. It really is a unique item in the Car world. However if it was questioned some simple research would have probably prevented this thread from ever getting posted IMO.....

JW
Kind of like early Mustangs and Falcons had 4 bolt wheels. Then Ford went to 5 bolt, back to 4 bolt on the Turbo Coupes and Mustangs in the 80s, 4.25 pattern.
If doby wants proof, take him a wheel.