9" gears are cheaper by like $30 over the 8.8. But you will spend more than that adapting disk brakes. Its crazy strong, but also way heavier than the 8.8. (I am adding 75lbs with the iron block, so the 9" will add 35lbs over the 8.8, and I bet the 8.8 is heavier than the stock GM axle) 100lbs just took a .10 off my et. every little bit counts on this build. Its a tight rope walk, quality, functionality and $ wise.
I can get an 8.8 full axle, from an explorer for $100-150 from a yard, last one I got for free because the dude didn’t want to look at it in his back yard at his house anymore! Specs are: 59.5" wide, with a 2" offset.
Stock 31 spline axles shafts are $50 from a yard, if that. I got 2 longs and 2 shorts for free from an off road guy who just didnt want them anymore either.
Ford Racing R&P set is $185 shipped.
Got a auburn full spool on ebay for $95 shipped.
Rebuild kit with bearings, seals, shims, etc. $60 shipped.
Work to build it:
Dump the fluid, pull the long side C-clip and remove the axle shaft. Cut the tube somewhere in the middle, doesn’t really matter where, doesn’t even need to be perfectly square. Take the half of the tube with the brake hub, toss it in the band saw, chop 2" off it. Again square is nice, but not really needed. Bevel both cuts. Measure the inside DIA of the axle tubes. Go to the metal store and get tube that has the same OUTSIDE dia as the inside dia on the tubes. Turns out metal supermarket has the EXACT size needed. OR if you are handy and anal about fitment, get a slightly larger outside dia, and turn it down on a lathe. Cut the tube about 8 inches long… no less. longer is better but totally un needed.
Now the axle tube is a welded seam tube, so you need to take an angle grinder and just grind a decent valley down the side, straight, on the 8" tube you have above.
Pound that bitch into the axle tube on the 8.8… the valley is so the weld seam doesn’t catch the sleeve and bind it, totally fucking you. Use a block of wood, so you dont mushroom over the other end of the sleeve tube. heck bevel both of them too to help slide in. hammer it in half way, 4 inches.
Now line up the short side tube you cut the 2" off, with the inside weld seam VS the valley you ground into the inner sleeve… that will keep the caliper mount facing the right way! IDIOT PROOF RIGHT! hammer that bitch back on now… as you get close to meeting the 2 8.8 tubes again, start taking measurements to make sure you dont send it TOO FAR, or you are fucked. Also hope you measured right when you made the cuts on the tubes, and you cut enough out, or they will touch, bottom out and you are still too wide. FUCKED.
Once its back together you are good to go. Put another short side axle shaft in the rear end, put the C-clip back on and get the TIG welder out. Tack 4 sides, alternating each one. The sleeve you hammered in will keep it aligned very well, the axle shaft, bearings and diff will also keep it aligned (that’s essentially what a real “axle jig” is doing). Pick the first tack weld and lay down about 3/4" of a bead. rotate it and pick the opposit tack, lay a bead. rotate, bead… etc. every time spin the axles to make sure its not binding. Let it cool in between if you want too… just take your time.
Both axles I did this way, the side I shortened actually spin BETTER than the oem side! dead nuts straight. Nothing fancy, no brain surgery work.
$490 paying max price on junkyard parts, new gears, new rebuild, used spool (add $80 for a new spool) and you have a built 8.8 57.5" wide, with disk brakes. :number1
If you are a boob! :rofl
I am gunna do ALL THREE. MAKE MY WORD!