Gears
 

I have a 99' gt and I wanted to know which gears to go with? I have heard 3.73 for the majority of the driving on the street, or if you drive most of the time on the freeways then you should use 4.10? Or should I just go with 4.30's?
Thanks

I have a 97 gt automatic and I am going with 410's. If you have a stick maybe 373. But what I am not sure about is which size the stock 97 and 99 gt's are. Are they the 7.5 or the 8.8. My .02

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The standard Cheap mods

I forget when they changed the rear end in the stangs but I know that they are 8.8 now. 8.8 is what my 91 had. As far as gears go, I'd say go with AT LEAST 4.10's. I had 3.73's and always wished that I had 4.10's or even 4.30's. This time around, I'm going with the 4.30's. No messin around.

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91 GT AOD: 14.71@91.78mph
SOLD!!
01 GT 5-speed on order: Ordered: 06/13/01
Build Date: 08/20/01

Finally people are starting to pick up on it. Yes at least 4.10's if not 4.30's for a 5 speed.

Bill



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00 GT, MAC Offroad H, Steeda Pulleys & Timing Adjuster, C&L 80mm, 4.30’s, Flows w/turndowns, UPR shifter, UPR Pro Series LCA’s, Lakewood 70/30’s & 50/50’s, 253.8 RWHP/292.8RWTQ
Best ET 12.91
Best MPH 105.49
M/M 100, 7085
2001 Mod Motor Shootout 2V NA Champion

Are 4.10s in a 5-speed okay even if it's a daily-driver only, no racing?

I've only posted this like 100 times. My car is a daily driver 75 miles round trip to work every day of the week, Monday thru Friday. My car has 56K miles on it in less than two years. I happen to race thus my choice to step up to 4.30's, otherwise I was perfectly happy with 4.10's. Great gas mileage and with traction nice improvements at the track.

Bill

Are you running drag radials Mustang92?? I was going to get a pair of Nitto DR's when I get the 4.30's. Seeing as how I still have a few weeks to get my car, I just might wait this year and get the gears and tires over the winter when the car is in storage.

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91 GT AOD: 14.71@91.78mph
SOLD!!
01 GT 5-speed on order: Ordered: 06/13/01
Build Date: 08/20/01

I haven't been running DR's for a while. Just regular Pep Boy Futuras, for the track I have a pair of ET Drags though. With nittos you can get your ET's pretty low though I got down in the 13.0's on 275/50/15's.

What about the right gears for the 99 Cobra?
Is there any different between GT and Cobra for changing gears?

Yes there is a difference because Cobra's have 1000 more usable RPM over a GT. The equivalant of a 4.10 in a GT is a 4.30 in a Cobra, 4.30 in a GT would be a 4.56 in a Cobra. If you see some track duty but aren't a regular racer I'd say stick with 4.30's. 4.10's in your car would be like 3.73's in my car which hurts your 1/4 performance because you have to shift right before the traps.

Bill

Would 4.30 be too much for a stock headed 96 GT w/NOS? I know for sure that I am going to at least 4.10, because the 3.73 were only a small step from the stock 3.27.

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96 GT: MAC CAI, ProM 87maf, BBK 70TB, MAC 2.5" h w/cats, American Thunder catback, 373, FMS pulleys, Ripper Shifter, 180 thermostat, MAC lowering springs.
Yet to put on: MAC control arms, Steeda timing adjuster.

It really depends on what you want. Okay if I put nitrous on my car I will either have to go with a taller tire, shift into 5th or change gears. For traction reasons I'm going to a taller tire (better traction, bigger sidewall). What you really need to do is look at what MPH your trapping currently and where you want to be in the future then work your gearing around that.

NA my trap speed is 96-97 MPH. With spray im assuming it would be 5-10MPH higher. Since it is an average over the end of the run I think it cross the line round 100MPH. Let me know how you cross and what gears you use. That should help me a lot.


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96 GT: MAC CAI, ProM 87maf, BBK 70TB, off road h, American Thunder catback, 373, FMS pulleys, Ripper Shifter, 180 thermostat, MAC lowering springs, MAC control arms, Steeda timing adjuster, cobra r hood/rims, aluminum driveshaft.

Well according to the gear calculators on the internet with 4.30's you'll be maxed out at 6K at 106.6MPH.

In my car with 4.10's I would cross the traps at 5400RPM in 4th. That is going 104-105. With 4.30's I'm crossing the traps at 5700-5800RPM in 4th going about the same speed.

NA though you don't want to be going through that high and RPM in your car because your power band drops off much quicker than mine does.

Your right. Last night I crossed the traps at 5000 RPM. My power dies after 5200 RPM. Looks like 3.73 are the ideal gear for a 96-98 GT w/stock heads. Going w/4.10 after the heads are changed would be my best bet.

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96 GT: MAC CAI, ProM 87maf, BBK 70TB, off road h, American Thunder catback, 373, FMS pulleys, Ripper Shifter, 180 thermostat, MAC lowering springs, MAC control arms, Steeda timing adjuster, cobra r hood/rims, aluminum driveshaft.