T56 vs 3650 gear ratios ?

Rusty67

Dirt-Old 20+Year Member
Dec 3, 2002
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Seattle area, WA
I have been waiting to upgrade to a T56 and I finally have enough money to do it but over the last few days I've found some data about the gear ratios that I didn't know previously. I'm wondering if this is actually true or not. I have a 2003 Mach 1 with a 3650. I read that 5th gear in the 3650 that came in the Mach 1's is .62 which is the same as 6th gear in a Cobra T56. Is this true ? Are there numbers on the trans tag I can check which would indicate which 3650 I have ? Another gear would be great but I also wanted a deeper overdrive because I drive a LOT of freeway.

If I'm going to end up with the same final drive ratio I don't quite have the same motivation to swap the trans out. Is there a better option out there for a T56 ? I don't want to go to a 6060 because I hate hydraulic clutch setups.
 
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Yep, the Mach1 got a .62 O/D. You might want to look at a T56 with a .50 6th gear -GM's F-bodies and Corvette and Vipers all came with that ratio and I believe most places offer that ratio as an option for the Ford-specific T56 too.
 
D&D has the T56 upgrade kits for the mustang. Includes T56 (optional viper spec with .50 6th), crossmember and shorter driveshaft.

If I was gonna pick one up I'd get the viper spec. Keep my 4.10's AND cruise on the highway at low RPM. Plus the torque rating is much higher. Doing the swap for a termi spec probably wouldnt be worth it IMO unless you just need the stronger trans.
 
i have no clue what final drive ratio's mean when it come to tranny's but have always thought about swapping to a 6 spd. Does it just have to do with what RPM it will top out at in each gear?
 
i have no clue what final drive ratio's mean when it come to tranny's but have always thought about swapping to a 6 spd. Does it just have to do with what RPM it will top out at in each gear?

Yes. I'm sure you are aware of how rear end gears affect your car. Trans gear ratios do the same thing except they only affect that gear.
 
D&D is a great vendor. mine came from them and 2 other friends have used them

stay away from 6 speeds inc. they took my buddies money and never shipped the trans. we have to file a chargeback to get the money. they gave us excuses for 4 months as to why it didnt ship out. they even gave us a fake tracking number