I've searched for an hour, and haven't found an answer. I recently bought a project from an old friend and it came with an 8 in rear end. I've got a 9 in, and several rear chunks, but he had already bought all the rear axle mounting hardware for spring, ladder bars, shocks and so forth. So my question is, will the carrier for a 2.70 (or so) work with a set of 3.80 gears? Also, is there a common 8 inch axle that came in the 3.70 to 3.90 ratio range? I'm working on a 29 Model A, with an early 327 sbc with a NV3500 5 spd manual trans, 7.50 x 16 Firestones, so it should pull a pretty good gear. Thanks in advance, Bill
Unlike a Chevrolet that has different carriers for different ratios, any gearset will fit in your carrier. They aren't quite as stout as a nine inch, but are plenty strong enough for most street cars.
I like the Ford 8", mainly because it came equipped with the "hat rotor" disc brakes, including the emergency (aka parking) brake. Rotors, pads, calipers, cables and shoes all readily available, at low cost. 4TTRUK
Are you sure you are not thinking of ford's 8.8 diff?? I have never seen an 8" diff with disc brakes, and even the Granad/Lincoln Versailles 9" diff disc brakes did not use the inside of the hat for the e-brake......... James
Thanks to all for the info, it is helpful. Would anyone know what models came with the 3.80 - 3.89 ratio, it would give me something to look for. Thanks again, Bill
That jumped out at me too. Does the center section come out of the front like a 9 inch or is there a tin cover over the backside ? Don
Hey Bill, We met at Mid-night Mass last summer. I have the blue 29 roadster. Someone told me that the 74/76 Mustang II V8 came with an 8 in posi carrier and some gear ratios in that range. Please take a look at 96/02 Crown Vic or Merc. Marquis for rear discs. They are almost a bolt on for an 8 in.
What he said... This is an 8" ford: eight inch in a nine inch storage box: The housing usually has two *dimples* on the back side, usually.... Most all the carriers are 28 spline n' they all use the same size yoke.
I was just under my heap looking at mine. No drain plug that I can see. Do you have to suck the oil out or will the bottom pinion housing bolt do it?
Mustang II and Pinto V6 wagons came with an 8" that often had a 3.40 gear and sometimes a TracLoc. Four lugs (4x4.25"), though. But if all you need is the center section, it comes right out.
Ya' gotta' use a suction gun to get all the lube out.. As far as gear ratios go, I've had an open 4:11 (too low) an open 2:80 (too high), a 3:55 track-lock (just right) and currently 3:80 track-lock (most fun) in my eight inch housing. All were either Richmond, Richmond Excel or Motive gear sets, except the 2:80.
I just did mine yesterday. The only way I know to drain is to loosen all the bolts and pull the diff from the housing. May be able to suck it through the fill hole. They are studs in the housing so will not drain when the nuts are removed. A friend of mine welded a nut into the housing in the place of the lowest stud position to drain the lube. Bill
Ya, I did some checking with Summit and others, and the ring and pinion prices aren't too bad, $150 to $200. So I'll probably go ahead and order up a set because it must be rare to find a 3.80 in this day and age. I'm thinking that ratio should be about right with the overdrive and 32.5 tall tires. My truck has a 4.11 and 31s with overdrive, and it cruses at 55mph at about 2000 rpm. Thanks again guys, this forum is great. Bill
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