big bolt pattern for 7-1/4 rear??

There are LBP and SBP 7 1/4 rears, but they each have there own axels, and housings. You cannot swap a LBP axle into a SBP housing.

It is possible to redrill the flange on a SBP axle, for LBP. I have a 5.13 SG 7 1/4 rear (bet you guys didn't know there was such a animal from Mopar) with redrilled flanges.