I have 62 Ford Falcon with a two speed transmission. I want install a 1964 Mercury Comet 3 speed manual transmission. I plan on buying the Mercury drive shaft, and pedal linkage as well. Do I need to change the gear ratio in the rear end with the different transmission, or will the stock Falcon rear end work?
The two speed and 3 speed transmission both have the same 1:1 high gear ratio. You'll get a better low gear ratio with the 3 speed, but you won't have the advantage of a torque converter. My guess is it will work ok with the existing rear gears.
You might look in the ref books & see if the manual cars had a stronger axle. Aspen/Volare(I know, diffrent cars) with 318 & A/T had 71/4 axle while the 225 6 cyl with manuals had the stronger 81/4 axle.
All the 2-speed auto Falcons I've seen (a handful) have had 3.50 gears, including my wagon. I don't know what ratio the 3-speed manuals came with, but as I'm pretty sure the C4 (3-speed auto) cars came with a 2.9 or 2.8 something-ish ratio. My wagon was converted to C4 by a previous owner.... With the 3.50 rear end, it's snappy on take off (the snappiness goes away fast) and has good torque for general driving. It's wound a little high going down the freeway but trucks up grades with ease. Even with the whole family and all the junk that goes with them, it'll climb a good grade at 60-65 and still have pedal left. Aside from giving up some fuel economy, I'm really happy with the combination. Sorry for the long winded response. Hopefully some of that helps.
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