Rear Advice

[WoodysCrabShack]

I have a 67 Mustang with a newly rebuilt 289 with around 280 maybe 300 hp. I have a 8" open rear in it now and wish to make it posi and put some gears in it. I have heard that the 8" will probably hold up but i want to know for sure. If it does i was wondering what company sells quality 3rd members but not too expensive. I have seen on ebay that some people custom build them for you after you bid on them, but im hesitent to do this. Any advice?

[Phillyfanfrombirth]

I helped one of my friends put a limited slip in his 68... We picked it up in Carlisle, but I don't remember who we bought it from.

We didn't have any problems with it and his car put out about the same hp (at the flywheel)...

[Gearhead999]

Check with one of our members named, Denver. I got a 8 inch 3.40 trac-lok last year from him. He handles 8 and 9 inch rears.

[okiedragster]

i helped a buddy of mine getting his 67 fastback rebuilt and he might have had about the same power as you before the new heads he got, but the 8 inch diff was definitly the weak link, it was the first thing to go out. if your gonna spend any kinda money on a rear end or a diff just go ahead and get the 9 inch and be done with it, there are so many resources for gears out there for the 9 inch that you cant go wrong. it would just be peace of mind to know you got something under your car you know you cant tear out...ive had a 9 inch in my dragster for 4 years now with a set of 5.13's and trust me i have whacked the hell outta that poor thing and its still in the car..oh yea thats with a wimpy 590 horse chevy sb...lol. i just hate to see ya get one and it break on ya after youve spent so much on it...

[rwhite65]

A lot of it depends on what your intentions are for the car. If you are going to keep your mild v-8 in it, then you are fine. I have a healthy shift kit in mine, and have abused it for years and years now, with an engine comparable to yours. If you decide you’re going to throw some sticky slicks under the car or something, then you need to follow okiedragster's advice.
I bought mine years ago from a place in Kentucky. Check the back of the classic mustang magazines; I think that is where I found him. About $400 to my door I believe, 4.10's with a trac-loc.
Ryan

[WoodysCrabShack]

Thanks for all the advice. It all really helped. Im going to show what you all said to the guy that is helping me with everything and decide what to do.

[Rev]

I've used an 8" in my '66 for the whole duration since the car was almost new. I now run 350-375 hp and the only problems I ever had was burning up Traction-Lock limited slip units. I did finally install an Auburn Pro limited slip and no more problems. My car does run a C-4, so there are no 5000 rpm clutch dumps. My experience is that the 8" is OK for what you describe.

I got mine from Currie in Ca. Not cheap, but the third member from him is good. He also has gears in any ratio you might want. My main advice is to get a durable limited slip carrier so you won't have to do what I did and keep rebuiling the Traction-Lock every 2 years or so.

Rev

[WoodysCrabShack]

thanks for the input about the third member. My stang is going to be a street peice. It may see the strip on a very limited basis. i will not be running slicks or transbrake at all. most likey just radials. i think I will go with the 8 inch since its in the car. Looking to put 3.55 s behind it. Richmond gears. Sound OK ????