Guys I might have solved the freeway gear ratio retro posi units. I will have to do a few more tests with set-ups but I could have something on the market we can use. I just want to be right on to be sure there are no stone unturned before I let it out for sale. Ok? Any interest? Jim This is for the 1968 -1970 2.73 2.56 2.93 gear ratios only posi unit. Large driver side bearing and regular 10 bolt bearing on the passsenger side rear diff housing. Just to be clear.
Would this allow conversion of a peg-leg to a posi rear for 68 - 70s? If so, I would be interested! - Bill
Yes if you have a peg leg and LIKE your 2.56 2.73 or 2.93 gear ratio this will work for that swap to posi and do nothing to the gear set application. You have to like that right? Jim The auburn takes care of the 3.23 and the 3.42 gear sets in the 68-70 Does anyone know about the 3.08 in 68-70 or whether there even is a 3.08 ratio. I need to know the carrier ring gear flange height. If you have a 68-70 rear with these gears please talk to me I could sure use this last bit of DNA to put the sting together . I have tried very hard to solve these trouble with this rear. and I think we have gotton some pretty decent stuff to use now. Jim
Just a note for the group: I have a 2.56 posi in my car. I LOVE it. If I could, I might go to a 2.29 ratio. Anyone who does any kind of real driving (i.e. freeway, etc.) will be very happy with a very tall ratio. There are several benefits to a very tall ratio: - You can use a standard TH400- no need to shell out $$ for a gearvendors, and cheaper/stronger than a built 200-4R - Gas Mileage - Quiet to drive on the highway (assuming you have decent mufflers and your weatherstripping is in good shape), and good engine longevity - Torquey Buick motors can still launch well (depending on your traction and suspension of course) - At any highway speed, I can downshift (in case a viper or Mustang comes up next to me) - I shift into 3rd around 110 MPH - No need to be towed to the track, or go 55MPH in the slow lane - You get to enjoy DRIVING your Buick! No need to leave it at home, then be stuck at a stoplight thinking "Oh, if only I'd brought my Buick, I could show this guy who's boss"... BTW, I ran a 13.3@107 MPH on my last time to the track this summer, and I get over 15 MPG with mostly highway (70 MPH) driving. The car weighs 4200# on the scales (with me in it). My 60' times are about 2.0, but I'm only using all-season radials and I could leave much harder with the proper tires. Hitting the nitrous puts me in the 11's at 118+. Then I can drive off the track and go home. I've driven 1000+ miles to Bowling Green several times. The moral of the story is that you can put a nice, stout 455 up front and keep the car enjoyable. Track-only cars won't want this ratio, obviously. -BC
Well , LOOKs good so far the 2.73 rear set-up beautiful. On to the 2.93 gears. Any one need a REAL clean 2.73 posi 68-70 rear for there car??? 500.00 takes it with a new posi unit 600.00 if you want it media blasted and painted up real nice. Jim I am serious once I am done these will all be up for sale. Along with the posi units to make your car posi and the correct conversion bearings too.
No, these are totally different posi units. Clutch type units. NO work is requred by you guys at all bolt it in and just adjust the side to side (backlash) I will usually supply a small shim pack needed with the posi. I will be setting up the 2.93 set I have in the next few days to see its fit. The guy that asked about the 3.08 gears...I have not seen a set in 7 years YET. Jim
So......I can replace my damaged carrier with this unit, and just bolt on the ring gear, set the backlash, and be back in buisness. With the two different sized carrier bearings installed, what kind of money would I be looking at? And how soon can this happen? Also, is a ring gear spacer available to run the 3.42's, but still be able to swith back to the 2.93's? :Brow:
Yes I never thought of that...I gues that is a possiblilty... I will have to measure the flange to see what size spacer would be needed. I would still prefer to do more setting up of more gear combos to see if any other trouble might come up from ratio to ratio. Jim I am selling the posi for 389.00 for the NEW posi and ad 40.00 for the carrier bearing pressed on and ready to roll. I will try to supply the shims to help with the carrier set-up. They are 1/2 the size of the old shim pack because the posi is slightly wider in the housing case. This is the reason I would prefer to check all ratios before giving it the 100% approval. The most you would have to do is recess gring the carrier webbing to clear the driver side main cap . I have NOT had to do that YET!ray: Yes as long as you have a factory or well set up gear in the housing that is of 2.56 2.73 2.93...Maybe 3.08 you can just swap the ring gear from the old open or posi carrier bolt it to the NEW posi and carrier shim it to the correct backlash and bolt those caps down to 65 ftlbs. Fill the posi fluid and run again.
Jim, Forgive me for asking even if you think your offer is clear. For $500 you are selling a complete rear housing with posi unit and axles installed?
i have an open 2.56 10 bolt 8.2 in my 72 lark are there any external differences in the 8.2's or just the side bearings just dont want to pull the cover for no reason i want to drop into the 3.42-3.90 range w/ posi just unsure what all i actually need , do i need another carrier or just a spacer? do you have any package deals for a bolt in conversion to these lower options if so how much (assembled carrier bearings gears and all ready to be bolted in w/ a pinion and adjusted)??
Hey Idaho, You should have a 8.5 if the rear is stock to the car. You have many parts available if you have this rear. If you do not have posi (open diff carrier) You might as well get the correct 3 series posi carrier 2.73 -4.56 and up If you just want to keep your open diff or you have a 2.56 posi unit YOU can use a spacer and just up grade gears. If you are going through all this and the car rear is untouched NOW I would suggest is the time to buy all the bearing new and this way it will be done for another 20-30 years again. JUST PM me- I can quote you out prices on everything you need PLUS I have all the stuff in stock to get it out quick. We do alot of 8.5 GM rear rebuild here. Take care and good luck. Oh if you want to have the rear IDed please just post a picture of the rear cover area and will help you out. Jim
Yah on the rear diff for 500.00. It might be a promotional deal for me. Remember it will not be media blasted clean you will have to work on all that stuff. It will have new posi and carrier bearings. Installed along with the axles installed...ready for your brake parts. The price goes up as the ratios get steeper as the want of those geared rears are higher on the wanted list.
Re: UPDATE 10 bolt 68-70 posi units for the high gears 2.56 2.73 2.93 Ok here is the update on the 68-70 posi 2.73 fit good 2.56 gears need the posi carrier webbing to be ground down / recessed so it does not hit the cap / inner housing area...the inner housing are can also be recessed if you want to do it that way too. THis is because I found out that 2.56 68-70 carrier is ALL BY ITSELF it is another .030-.040 to the left. so nothing else can be done. The 2.93 rear is next. should have it worked out by tuesday. Keep in tune. more to come. Jim
well i do believe it is the 8.2 not 8.5 (no ears on bottom of housing) but aren't there 2 different 8.2 rears or am I understanding wrong ya I know I "should" have an 8.5 but its been swapped out bummer
Would like to know about the 2.93 posi as well. Have a 69 Sportwagon with the "economy" axle that is definitely the 2.93 unit. Just the posi unit would be great. Thanks!
2.93...Fits right in fine. Ok all I need to know is if a 3.08 68-70 gear even exsists and what carrier it uses. So far we started out with NO posi units and NO gears for the 68-70 rears....NOW after about 1 year we have a 3.42 gear set 3.23-3.42 posi unit and a 2.73-2.93 posi unit. It will work with 2.56 gears but will require grinding of the posi units webbing on the ring gear bolt side of the unit. I will probably just grind this area for most customers to be sure that when you are installing it you do not run into any trouble...My special touch for buy from me. Ok? Jim so 389.00 will get you this unit 40.00 will get you the bearing you need new and ready to go and another 10.00 will get you the shims so you have them for shimming properly. The original shims will be TOO wide and not usable for this install. I have to charge something for them...as I cost me money to supply them in both sizes. If you buy a whole rebuild kit for 95.00 it will include everything you need to set up this rear 68-70 including carrier bearings and pinion bearings pinion seal shims pinion and carrier BOTH sizes gasket marking compound NEW ring gear bolts lock tight...EVERYTHING but the axle bearings and seals which also can be included for 65.00 (includes seals and bearings x 2) Just PM me or hit my jdrace site WHICH SOON will have pay pal buy it now items including this posi unit. and rebuild kit. I prefer to go around pay pal BUT I have to do what I have to do these days. Take care guys and hope everyone had a GREAT NEW YEAR! Jim Mitschke
