Spring perch mount width HELP F Body

Any help out there guys. I can't measure my Volare right now and my buddy needs the measurments. I am installing a B body 8 3/4 in my Volare. Would it be best to tell the guy doing it inside to inside measurements?? Thanks in advance for any help, info. Not to go on and on but read somewhere that I should toss the rubber bushings and install A/B lower plates? Would I have to switch shocks? Thanks again for any help.
Jeff

Looky here! http://www.moparts.org/Tech/Archive/axle/17.html

Should be ok on the shocks.

more problems then that putting an 83/4 in a F body. iso-strut B.S.,different shocks,cut the driveshaft,change the locating bolts in the springs,spring mounting plates,different u-bolts,spring hanger bolts that wring off in the frame.And you should mount the rear in the car with the spring perches loose so you can get the pinion angle right then tack weld them.-LOOK BEFORE YOU LEAP.

I put a b body 8 3/4 in my 80 Mirada. You need the older style shock plates and B body shocks. You don't have to mess with the spring perches at all. Even my pinion angle was still in spec.

B body perch width is 44", FMJ is 44.46, that's less than 1/4" per side, the springs will easily move that much, my housing dropped right onto the springs no problem. You'll also have to buy new spring center bolts... If you remove all the iso clamp stuff like I did your old center bolts will have a funky 11/16 (I think) head on them, you need plain old regular 1/2" ones or whatever size they are. Get your drive shaft shortened and you're set.

Thanks for all the info guys, had no idea I had to shorten drive shaft
Read somewhere else "welding in a washer into the axle housing perch hole is the only fabrication need to switch to the A/B lower plates"