gears, need help

Is it a vert or regular gt? 5spd or auto? If 5spd go with the 3:73's, 4:10's if an auto. Streetability you're worried about?? The thing will be a blast from what it is now. With a 5spd, 303rwhp and 3:73's in my car, I still got 24-26mpg on the highway and 17-20 around town. You'll love them, go for it
Mike.

If you ever cruise at 80--90mph,,you might not like 373's..I agree for more performance go 373's,,if you do alot of highway driving you might wanna think 3..55's.JMO!!

Go with the 3:73's and dont worry about highway. I believe my car was around 2600@75 or so, somewhere in the ballpark of that. Do the gears and hang on. Do the rebuild kit when do it.
mike.

Do a 87-88 Thunderbird Turbo Coupe rear end swap and get either 3.55's or 3.73's and disk brakes as a bounus...

It takes 2 guys the first day to get the old rear end out and the new one bolted in place. It takes 1 guy another whole day to do the brakes.

Auto trans Turbo Coupes come with 3.73 gears and manual Turbo Coupes come with 3.55 gears. I choose 3.55 since I do more highway driving.

You will need a several sets of fittings, I recommend that you get them from Matt90GT's website, http://www.svo73mm.cjb.net/. Read Matt's instructions thoroughly, everything you need to know about the brakes is all there. You need to be patient and follow all the internal links, and there are many of them. You will need 2 fittings in the rear to adapt your old brake tubing to the TC disk brakes. The fittings go between the steel tube and the caliper brake hose. You will need another set of fittings to make a 2 port to 3 port adapter. To make life simpler, just buy the kits from Matt. You could piece them together, but it's not worth the time unless you work at an auto parts store with all the fittings ever made. You will need to drill the quad shock mounting holes 2” below the holes drilled for the Turbo Coupe mounting points. The bolts are metric, so don’t loose them or the nuts. A 15/32” drill should be about the right size unless you have access to metric sized drill bits. Going without quad shocks is not an option unless you have aftermarket parts to soak up the wheel hop.

You will need a proportioning valve, Summit has one for $40 + shipping.
You will need a kit (FMS makes the part) to gut the stock proportioning valve, Summit also has that, about $10.

You will need a new master cylinder, see Matt's site and make you choice. I used a 94-95 Mustang master cylinder. Note that rebuilt 94-95 Mustang master cylinders do not come with a reservoir. That means a trip to the junkyard and some more money spent.
Your brake pedal may be very hard and almost impossible to lock up the brakes. I had to replace the front calipers with 73 mm calipers from a 91 Lincoln Mark 8 to get the braking performance up to par.

See http://www.mustangcentral.net/tech/brake.html for help with the emergency brake. The ebrake handle on 87 and later models must be modified by removing the spring, and tack welding the pawl and ratchet assembly.

Bleeding the brakes will require 2 people and some coordinated effort. I don’t recommend using you wife or girlfriend to pump the pedal – they get offended when you yell at them. I used a homemade power brake bleeder constructed from a garden sprayer and some fittings from Home Depot. It cost about $25 and was worth every penny.

All in all I have been very pleased with the results.

i have 3:73 and love it. but make sure you buy an alumin. drive shaft also. so you won't have to deal with vibration in your drive train.
no offence to jrichker, but for all that you mention above. he might as well rebuild what he has with a new posi, and new 31 spline axels. and for rear disc brake conversion. check this place out. http://www.p-s-t.com/ford/fodbconv4.html

If you dont care about highway,,go 410's.Gears cost 189.00,,get Ford Motor Sport gears there the quietest,,and labor is around 200 Beans!,,But jrichker seems to know his sh@t!!! Having disc brakes in the rear is a bonus

89five0 said:

well my car is an 89 gt with about 125,000 miles on it an still running strong. so far this is what mods are done to it: bbk shorty headers, matching h-pipe w/cats,american thunder flows, msd distributor,and plug wires, also bbk CAI fenderwell. i was wondering if 373 gears would be a good upgrade for my car and still making it streetable? Also i am thinking of getting some U/D pulleys what do you reccomend? With these mods should i be able to reach the 13s? also any other easy mods do you suggest. thanks

Click to expand...

Yes those mods should get you 13's...by the way go 373's...