8 or 9 inch posi finder help- guru's?

68converted · Jan 21, 2004

Ok, I just started to work on putting gears on my 8" LS diff, only it is not a "posi" unit it is open. This all started when looking up some info for a buddy's car. Now I have the same problem he has. What types of cars, vans, had an 8" or 9" Trac loc? I will probably be pushing 300 rwhp when I am done with my conversion and with an 8" open rear it is going to suck bad. I priced out a 9" posi rear with 3.55 gears (true bolt in) for $1200 wow. I am sure I can do way better using a salvage yard donor. Does anyone know if the mid to late 70's vans have a 9"? How about posi.

I have seen a few do the 8.8 conversion. I got one for free (well a trade for a C4). Can an 8.8 take a good amount of pounding? D. Hearn talked about one type at over 280#'s and another at #150?#'s. What Mustangs came 94-98 mustangs came with posi rears? I know this is a lot but finding a 8 or 9 Trac Loc from a early mustang, cougar, ?? is nearly impossible now. Can anyone shed some ideas as to where we can look for alternatives on the low $$ side.

351LX · Jan 21, 2004

The best place to find a nine inch trac-lok is a Ford truck but most of the ones from the early 70's until the mid 80's when they stopped using them are 31 spline.Look at the door code for a letter and a number and then verify it is a trac-lok by seeing if both wheels spin the same way.Next choice would be a van.Passenger car nine inchers are still out there but are getting rarer.Your best bet is to find a wrecker that has a lot of turnover and visit them frequently.There are lots of guys out there beating the bushes for trac-loks so the slower wreckers will be picked clean already.

68converted · Jan 21, 2004

351LX said:
The best place to find a nine inch trac-lok is a Ford truck but most of the ones from the early 70's until the mid 80's when they stopped using them are 31 spline.Look at the door code for a letter and a number and then verify it is a trac-lok by seeing if both wheels spin the same way.Next choice would be a van.Passenger car nine inchers are still out there but are getting rarer.Your best bet is to find a wrecker that has a lot of turnover and visit them frequently.There are lots of guys out there beating the bushes for trac-loks so the slower wreckers will be picked clean already.

Thanks for the tip on wheel spin, I never knew that. Time to start beating the bushes...

What am I looking for on the door code? Where can I find codes/decoder for trucks and vans?

Doc Voodoo · Jan 21, 2004

http://www.dfwmotorsport.com/Fairlane/9inchrearends.htm

http://www.ultrastang.com/Rearinfo.asp?Page_ID=1

http://www.sunflower.com/~vervaecke/versailles.htm

the ultrastang one i think is the best link

Doc Voodoo · Jan 21, 2004

http://www.ultrastang.com/Rearinfo.asp?Page_ID=1

cheak this web page out

351LX · Jan 21, 2004

Here is a door code chart from the Ford truck Enthusiast site.http://www.ford-trucks.com/articles/axlechart.php

GaPonyFarm · Jan 21, 2004

Use the 8.8 rearend and make it posi, if you need to. Its nearly as strong as the 9", but much lighter. You can easily get the posi gears and 31 spline axles, if necessary, for much less than the $1200 for a 9" rear. If you go to a 9" from a truck, you'll need to cut the housing and weld in a new race and flange. You all need new axles, or maybe cut down the originals...just too much hassle for my taste. You'll like the 8.8".

bnickel · Jan 22, 2004

i would keep the 8", go the wrecking yard and look for any late 70's fords you can find with the 8" rear as ford strted phasing the 8" out in the late 70's and they had plenty of trac-loc units to get rid of. the best bets would be v-8 and v-6 mustang II's, most any v-6 pinto especially the wagons, v-8 granadas, monarchs, most late seventies mavericks and comets even the straight six cars had 8" rears in them. your best bet for finding a trac-loc with decent gears would be the v-6 pinto wagons, just about every one i have seen has had a 3.55 trac-loc in it, scored a complete rear out of one for my 78 mustang for 50 bucks once and it was a 3.55 trac-loc. also when you are searching make sure you read the tag on the center section it will tell you if it is a trac-loc or not, should read something like 3L 55 for a 3.55 trac-loc or 3L 40 for a 3.40 trac-loc, etc. and since it came from a pito you can usually get them really cheap. the 8" with trac-loc should hold up to 300rwhp just fine as long as you make sure it is set-up correctly, new bearings and clutches etc. good luck and let us know what you find

D.Hearne · Jan 22, 2004

I've got a 77 Lincoln Versailles 9" rear for sale in the classifieds here on StangNet. Best bet for a Trac-loc 9" chunk is a Bronco or 4wd pickup. Not all had 31 spline axles, most had 28. And full size Ford 9" rears are a dime a dozen here where I'm at. I have three hangin in my shop. For what you can buy and narrow an 8.8 for, you can also do with a 9". I don't recall the thing 68converted's reffering to about 150#'s and 280#'s. you got me stumped there.

bud4660 · Jan 22, 2004

GaPonyFarm said:
Use the 8.8 rearend and make it posi, if you need to. Its nearly as strong as the 9", but much lighter. You can easily get the posi gears and 31 spline axles, if necessary, for much less than the $1200 for a 9" rear. If you go to a 9" from a truck, you'll need to cut the housing and weld in a new race and flange. You all need new axles, or maybe cut down the originals...just too much hassle for my taste. You'll like the 8.8".

If the 8.8 is out of a mustang it is going to cost more to use that in an older car. First it wasnt set up for leaf springs. Then you need to get the axle tubes welded into the center section so they dont pull out. If your going to race with it you will need to do C-clip eliminators and bigger axles.
The 8" and 9" pumkins are alot easier to work on then the 8.8 is. I had a 8.8 that was in my 98GT built acouple years ago. Spent over 2k on it for street use.
Not sure on the $1200 dollars?? Most posi units run $4-500 and gears run around $300 axles are another $300 or so. Unless labor to put it together was high?? You can buy 9" housing from $250 up from most companys that do rearend build ups.
Get you a ford posi unit and good set of street gears and use the 31 spline axles and you will be set.
The stuff ford used back in the 60's behind a big block that made more HP then you are looking at was fine.

71vert-pga · Jan 22, 2004

Call Freddy Sleffel at Mustang Masters in Jacksonville, FL at (904) 724-3927.

Freddy has dozens of Mustang rear ends from every year with just about any gear ratio. He has 8 and 9 inch in both conventional and locking. Expect to pay around $400 to $600.

67GTCOUPE · Jan 22, 2004

71vert-pga said:
Call Freddy Sleffel at Mustang Masters in Jacksonville, FL at (904) 724-3927.

Freddy has dozens of Mustang rear ends from every year with just about any gear ratio. He has 8 and 9 inch in both conventional and locking. Expect to pay around $400 to $600.

Everyone is SMOKING CRACK! 400 to 600 for a center section!!!!! Ha HA what a rip off!!!!

I look around for older smaller yards.....I have a connection where I get the entire rear for $100.00!!!!!

68converted · Jan 22, 2004

Man, you folks rule! I started a search on info when I posted this thread. I now have 10x's the info I did last night. Awesome! I may have a line on an 8" posi unit, do I just pull the guts from my 8" and replace witht he posi unit? I know that I have to slip out the axils but what else would I need? The rear just got new bearings, seals, etc. It seems a huge waste if I try to replace the entire rearend now. What is the story on the posi center swap?

68converted · Jan 22, 2004

D.Hearne said:
I don't recall the thing 68converted's reffering to about 150#'s and 280#'s. you got me stumped there.

Sorry, I it was concerning the weight of the rear ends. Saw the numbers on a post you had commented on. The guy had picked up a mountianeer rear or something...

bnickel · Jan 22, 2004

68converted said:
Man, you folks rule! I started a search on info when I posted this thread. I now have 10x's the info I did last night. Awesome! I may have a line on an 8" posi unit, do I just pull the guts from my 8" and replace witht he posi unit? I know that I have to slip out the axils but what else would I need? The rear just got new bearings, seals, etc. It seems a huge waste if I try to replace the entire rearend now. What is the story on the posi center swap?

pull the axles, unbolt the old pumpkin and bolt the new one in, slide the axxles back, make sure all the bolts are tight and you're done. make sure to double check that the pinion yoke on the new diff is the same style as the old one, though. this would be the most cost efficient way to do it, as you'll have to have a new driveshaft made if you swap to a 9" or 8.8", assuming your car still has the original shaft which is a 2 piece shaft with a vulcanized rubber vibration insulator between the inner and outer shaft. because of this you will not be able to modify the original shaft.

68converted · Jan 22, 2004

bnickel said:
pull the axles, unbolt the old pumpkin and bolt the new one in, slide the axxles back, make sure all the bolts are tight and you're done. make sure to double check that the pinion yoke on the new diff is the same style as the old one, though. this would be the most cost efficient way to do it, as you'll have to have a new driveshaft made if you swap to a 9" or 8.8", assuming your car still has the original shaft which is a 2 piece shaft with a vulcanized rubber vibration insulator between the inner and outer shaft. because of this you will not be able to modify the original shaft.

Going to an aluminum driveshaft so no big deal on the yoke change. I thought i would be that easy. I am going with the new posi insert then; way cheeper than a whole axle setup! Thanks

taylor4g63 · Jan 22, 2004

IF anybody can hook me up with a 8", 3.55 (preferably) 3.40 or even 3.25's with traction lock for cheap let me know. it doesn't matter if it needs to be rebuilt. I would be willing ot pay someone a lil bit and pay the shipping charges...

taylor4g63 · Jan 25, 2004

anybody???

1slyfox · Jan 25, 2004

http://car-part.com/

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