I just did gears in my 1990 Gt AOD, stock with bolt ons. I did not listen to the know it alls on here and went with 3.73's. The 3.73's made a big difference, but I could kick myself in the ass for not listening to these know it alls. If I had to do it again 4.10's would be a must!!!!!
If your going to spend the money only do it once! GO WITH 4.10
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1990 Mustang Gt auto,1.7 Roller rockers, Gt-40 intake,Mac shorties,Mac o/r h pipe
Mac exhaust,Cobra R wheels,Sub frame conectors
Smog delete,Under drive pullies, BBK cai, BBK 70mm tb, electric fan, 3.73
I also went with the 373's, which I like...but cant say it was a huge noticable diff...but if I did it again...would prob have to hit the 410's.....the 373's arent as bad on the tac as I first thought it would.
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1988 GT Vert 70K
BBK Fender Cold Air, Ford E303, Cobra Intakes, Kirban Adj Fuel Reg, FRPP 65mm TB, 19# Explorer injectors, MAF Conversion, TF Valve Springs, BBK Equal Length Shorty's, KYB's all around, Magnaflow 2.5 high flow cats H pipe, American Thunder's, 3.73's, Speedo gear, AOD w/Performance Automatic street/strip valve body, Overdrive A+ Super Servo, 2-3 Accumulator upgrade, Urethane motor and tranny mounts, Smog, EGR and A/C delete
The 3:73 for more of a daily driver that's used on the highway, 4:10's for an around town car. I have an AOD and the 3:73 gives plenty of grunt, although the 4:10's would be more fun.
The choices are:
3:73 - overall performance, good on the highway, good gas mileage, can be driven everyday on the highway.
4:10 - more take off, acceptable gas mileage, better if you intend on racing.
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MOOG Certified Tech. For mods and sound clips, see profile and gallery.
Ask me why I ran "only" a 13.54.
Member: NMRA Member: White Mustang Registry #362 Member: Fuzzy Dicer
1988 Mustang GT Automatic, Gears? 
