Which is why I asked which rear axle he has. The BBP 8.25 is narrower than an A body 8 3/4" with BBP axles. On a duster a 4" backspace with 15x8's and a BBP 8 3/4 would put you into the quarters with 255's.
Was there a reason for only running 4" of backspace on your barracuda? I know they have plenty of room out to the quarter, but those measurements should leave quite a bit of extra space on the spring side with 255's.
The reason I choose 4" BS is because after drawing everything to scale on my CAD program, it was the best overall fit. No spacers for me. The CAD showed 4.25" would work but it was pretty tight. Just being cautious. May try 275's just for grins.
