3.25 vs 3.5 in 69 Mach FMX?

[dkm004 11]

Hey guys, Im looking for some input.

 

My 69 Mach has a mild 351W FMX and an open 3.25 9" rear end in place. Im planning on going posi and toying with the idea of going with 3.5 gears while its apart. The idea being to wake it up a bit down low. The car is mostly city driven with the odd highway trip here and there.

 

Your thoughts/ experience? Cheers!

Edited May 5, 2014 by dkm004

[RPM 1,190]

That's the same set up I had, and going to! It's not on the road yet, but should run good with the 3.50 gears and traction lock.

 

Bob

[maxum96 32]

If you want something decent out of the hole and don't plan on much highway use, 3.50 gears will be a good choice with a non-OD transmission.

[ashleesmach1 28]

I have 3:50 gears as well and the engine does run near 3000 rpm at 60 due to the 1:1 3rd gear on the fmx trans. its not bad but I kinda wud like an aod myself, if they were not so darn expensive and made better.

[takoarm 10]

https://www.yearone.com/Product/1964-73-mustang/271601p19

[fvike 173]

I have a FMX with a 3.70 Detroit TruTrac. It's ok, on long drives it doesn't tire me out any more than my old 2.79 open diff setup did.

[maxum96 32]

https://www.yearone.com/Product/1964-73-mustang/271601p19

 

 

That's a deal at only $7,829! :eek:

[takoarm 10]

That's a deal at only $7,829! :eek:

 

6 speed though I am thinking about it myself.

[maxum96 32]

6 speed though I am thinking about it myself.

 

It may be a 6 speed, but not worth almost 4 times my 5 speed TKO.

[stangme428 33]

just as a reference.... in my build i have a T56 with a .50 6th gear and 3.77 rear gear, and i'm turning 1800 rpm at around 75 mph... so unless im on the hwy .. no go with 6th gear... make sure which 6 speed final gear you get....