by springtime i hope to have found/installed a locking rearend out of a mustang II. as i understand it... certain II's did come with locking rearends, that are a bolt-in fit for my 8" maverick housing. i understand that the axle splines and everything are compatible. my question(s) is... has anyone done this, or seen it done? are there any special concerns when doing this? and is that mustang II rearend strong enough for a V8? thanks RR
Just slid the axils back take the nuts off holding it in place have new gaskets and some rear end lube and some friction modifier but I do not think there is a lot of the Cobra II around and to put a used posi or trac-lock unit in that old might be asking for a head ace You can find posi centers at swap meets and even on e-bay and the net, I think there’s a person that has one name Steve = cometgt1974 has a 8” center section I think for sale
roadrage, I have just done this very thing except that I wasn't able to find a posi equipped unit, so I just took one out of a 78 M-II with 3.40 gears and it bolted right in as it is an 8" just like my Maverick. I like you hope to find one with a posi but won't hold my breath. If you find one it should be plenty strong enough. We have a 4.62 geared 8" in our race Pinto and it runs 12.20 1/4's and hasn't broken yet. A friend had a 3.50 geared 8" in his studebaker behind his 383 stroker Chevy with nitrous(not "NOS") running 12.50 1/4's with no problems.
8" trak-loc This guy apparently can convert your open rear to a posi for 200.00 plus shipping. I don't know how reputable he is! MAE RACING RT 10 & JCT 1306 PO BOX 399 GARRISON, KY 41141 606-757-3221
I had some place take my open 8" rear end and convert it to a posi using a posi unit from an 8.8" rear-end. Not sure how it was done....something to do with taking it to a machine shop and drilling and tapping holes to fit the 8.8" posi to the 8" ring gear or something.
yes the rear end is strong enough for a v-8. i've got a 78 mustang II cobra sitting in my back yard right now. plan on putting the front end under my 71 mav eventually, came with a c4 and 8" posi (haven't checked yet to make sure). the posi is probably going in my 64 fairlane. the car had a 302, .030 over, forged aluminum pistons, crane gold roller rockers, and numerous other parts. 302 heads, screw in studs, and guideplates. the guy that had it drove it until he had a cam problem. sold everything to me for $400.
I did it... I swapped in a 3.55 geared Traction-Lok from a Mustang-II. It is a direct bolt-in with no other modifications. You just need a new gasket and use a limited slip additive with the Traction-Lok. To answer your other question, the 8-inch rearends in the Mustang-IIs are the SAME as those used in Mavericks, so they are not weaker in any way. It is also the same rearend used for both V-6 and V-8 models. The V-8 models will not have 3.55 gears, only the V-6 models do...
I was searching the posts and came across this one. Do all of the 6 cylinder rear ends with 3.55 have posi? If not, how do I tell which stangs have posi?? I really need to know. Thanks, Preston
Check the tag on the rear... if it's a Traction-Lok it will read 3L55. Otherwise it will read just the gear ratio without the "L". Supposedly there are other junkyard tricks to tell, but I've never found them to be reliable. The tag never lies. Sam
Craig, your conversion using an 8.8 in an 8 setup is interesting. The two setups internally are totaly different in how they mount as well as the size difference. As you know, the 8" has threaded back- lash adjusters on each side to move the ring gear. The 8.8 uses shims between the bearing cap mounts. I have both carriers spare and will look at them to see how it might have been done. As you can tell I'm a little learey of this.
That does sound interesting considering Ford Motorsports dont make a trac-lock for the 8". If the 8" and 8.8" ring gears have the same bolt pattern, it seems it would just be a matter of machining the shoulder where the ring gear sits. Since they are both 28 spline axles, the carrier bearings are probably the same or at least, the carrier can be machined to accept the 8" bearings. The spanner nuts can easily take up anydifference in width.
Country, the easiest way to tell if there's a posi in something is turn one wheel and if the other turns the same way it has a posi. then have someone hold one while you turn the other to see how good the clutches are, it should take some effort to turn while holding the other. On a side note I got a pumpkin with 3.55's from a mach1 MII and it didn't have posi. so the answer to your second question is not all 3.55 had posi.
