I found out that this mystery rear is in fact an 8-1/4 that I picked up last weekend, so now that I know for sure, I can go ahead and start acquiring
parts to build it up the way that I want for my Volare. (Gotta dump the 2.2 open ratio that came with this rear!)
I see a few different posi (OK... Sure Grip) carriers available on Ebay, 1 I have bid on, and have 2 others on my "watch" list. All that specify brand
are Auburns. I know that sometimes, rear ends require a different carrier based on the ratio that is being run. The one that I have bid on, is a "2 series", which the seller says is for a 3.55 and numerically higher gear. One on my watch list is not specified, the other is a "3 series" which that seller says is for any gear 2.76 and numerically higher. According to him, the 2 series is for ratios numerically lower than 2.76. I have e mailed both RAndy's Ring and Pinion and Drivetrain Specialties and have not yet heard back from either.
I called an 800 number to National Drivetrain on my lunch today and the guy there says that in all the 8-1/4 rears that he has ever worked on, he doesn't remember any different carriers for different ratios. In other words, any carrier for any ratio, as long as it fits the 8-1/4. I don't want to get screwed on this and get stuck with a boat anchor that I can't pawn or trade, either. Who is right?? I am running an A833 OD for a trans, and either 245-60-14 or 235-60-15 tires. (Depends on which rims I decide on.) I am leaning towards a 3.55, but may go to a 3.23.

Don, as far as I know, all the carriers are the same. I have a buddy with one and a set of 3.55 gears for sale that is new. He never said anything about it being a 2 or 3 series.

I thought the only ones that did that were GM 10 and 12 bolts.

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Official Cookie and Mater Tormentor.

The 2.45/2.24 carriers are different (I 've seen one's that looked narrower/skinnier) and will not accept the 2.76 and higher ratio ring gears....The fix for that is to pull a carrier races and ring and pinion out of a car/truck and install into your 2.45 or worse axle housing.... (Of course I'd like to see one of the 'Sure Grip' 2.45's that was possible to get from 1973-1976....boy, that'd be a real screamer....).

-D.Idiot

D.I beat me to it

only other thing i have seen is that the carrier bearings seem to have switched along the way to different sizes. its kinda like the 8 3/4 deal where any sure grip will fit any case as long as you have the right bearings for it. i found this out when i put a '96 suregrip in my '73 housing. just went and got the bearings for a '96 and presto--problem solved.

--chad

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74 swinger slant 6, the slowest, most fun car i have ever owned.