How to modify an 8.8"

[84_GT350]

Somebody recommended to me that I modify an 8.8" rear end to accept 9" tube ends instead of getting C-clip eliminators because my car will see lots of street time and I don't want leaky seals. How do I do this, where do I have it done, and how much does it cost? Hehe. I'll probably get 31 sline axles and I'm clueless as to what I'll need to get this done or how to do it. I'd consider an actual 9" rear end, but I'll be getting a torque arm and panhard bar and I don't think they'd work with a 9" rear. Besides...have you seen the prices for good 9" rears? They're like $2000+ complete.

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1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s