Hoping to re-open this discussion for still more advice. I too have similar issues: scored a '73 complete suspension from a Dodge Dart for Big Red, 8.25 rear with 5 leaf springs, 2:71 open rear (size confirmed), BBP, big discs up front, big drums in the rear, correct A-arm, yadda yadda.
Happy with it and the price. All stuff in excellent shape. Sent the rear out to a local reputable shop to rebuild and set up with the off-a-shelf, NOS 8.25 Sure Grip that came with all the other goodies. . .comes the sad report in today: the carrier is .25" shorter than the open carrier at the ring gear mount when they are set side by side; the carrier adjuster ran out of adjustment trying to set the pinion gear tooth depth of engagement. There does not commercially exist a spacer, and longer gear retaining bolts would be needed as well- not that that is advisable anyway.
Apparently, I came away with a "jackpot" of sorts: the NOS Sure Grip I scored is for '70-'74 8.25 rear with 2.52 or 2.45 ring and pinion! In other words, it is a paper weight or boat anchor; who would want Sure Grip in those gears? I can return it for the $100 I got it for, but that's all he has available (closing parts warehouse deal).
Actually, I want the 2.71 for fuel economy and low RPM on Texas Highways at 80 mph (Besides, I already own the gearset!) ;-) Car is set up with poly bushings, frame ties, Formula S springs and torsion bars, performance shocks and front and rear sway bars to cut nice corners at speed in the Hill Country around Austin. Maybe do some light parking lot cone rallys some day. The 2.76 gearset (original was a 7.25 rear with a Sure Grip! Go figure. . .) formerly under it did well enough for acceleration in first in the 904 for over 300,000 miles of my abuse. . .and it worked okay with the mildly worked 318 I have in it now. . .but it was tired and needed a change to something heavier.
Now my choice to finish this part of the build seems to be Eaton Truetrac or open rear. Seems Mopar Performance does not offer a Sure Grip for anything taller (numerically lower) than 2.76. . . So says their website. . .
So, who likes Eaton Truetrac, is it worth $400 more on this money hemorrhage I'm into, will it make any real difference in how the car drives and corners enough to notice? I know a number of us here do auto cross and road rallies- what do you do for your rear end with regards to driving those corners? Probably very seldom see snow or ice, seldom rain slick streets- but it will be driven.
Thanks as always guys and gals. I haven't been on here for far too long due to various personal hills to climb this year. . .but still plugging along on her here and there. Just passed 2 years in a 1 year personal finishing goal. . .you know the drill.
I know, I know- Pictures!
:-D
Mike