Contrary to what you may have read on the web, the vast majority of Mustang II's had open rear ends. I owned a 77 Mustang II V8 4 speed that I purchased new and could not order a Traction Loc as an option. Finding an 8" with the extra rib case and Traction Loc is quite a challenge. Most of us that run the 8" have had to build one up with a new Traction Loc and an aftermarket set of gears if you want 3.55's or higher ratios.
Plenty of guys out there making third members with traction loc (Posi) for the 8" ford rear end. Of course they are running about 700-900 bucks but you can pick just about any gearing between 3.0:1 to 4.55:1. You can of course upgrade your own third member but after buying all the "quality" parts necessary to do it you will already pushing close to 5 bills. Add the pain in the ass of assembly, shimming, making sure the bearing pre load is correct and the gears are making contact in the correct manner a lot of people would rather just pony up the extra $300. I got tired of searching boneyards and just bought one. Now I'm rebuilding the carrier I pulled out to be Trac Loc. If goes well I'll most likely list it on here for sale.
I had a third member (equa-lok) 3.73s made for my Daughters stroker by Currie years ago .. Very pricey ..but it has never given us any problems. Doesn't make noise and really hooks things up . I'm sure you could find someone to make you a equa-lok setup locally if you shop around. You'll need ring and pinion and clutches and then the set-up. I'm having one made for my 70 Maverick which has an 8" inch Third Member already with 3.25's . It's going behind a 5 Speed OD tranny . Cometized (Chip)
If you are going with a 5 speed OD Tranny, I am surprised you arent going for a taller rear end gear. Like a 3.55 at least.
Agreed. Depending on what you're after and what size tires you're running. Currently I only have the stock 3 speed manual in my car but am running 3.55:1 as I RARELY do over 80 mph. So it's not near as mind numbing. Off the line quickness and acceleration is much more important to me. With a 5 speed OD and 4.11 gears you'll just about give yourself whiplash of the line and still have plenty of room at the high end. 90 mph @ 3000 rpm and only about 4000 at 120 mph. Again depending on your tire size (this is with a 26 inch tire diameter). Again. It all depend on what performance you're wanting from your car.
