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Guys -
I have a 69 that was originally a 4 speed but was converted to a TH400 by the previous owner. He also changed out the rear end to a Chevy 12 bolt 3.73 ratio.
My question is whether or not I need to be concerned with the gearing of the 4 speed that I install? Would there be an advantage one way or another when it comes to running a Muncie M21 with a 2.2 1st gear versus a Borg Warner Super T10 with a 2.43 1st gear?
Aside from the fearing question, what are your thoughts n the BW versus the Muncie?

Thanks for your input.
 

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I would pick the Super T10 because the gearing is more spread out and that would be better for a street car. Since the Muncie is not an M22, the M21 vs. ST10 are not that different.
 

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Well, I'm gonna go the other way. I ordered my new '69 RA3 GTO, with 3.90 gears and the 2.20 close ratio Muncie. I loved it, and after 60,000 + miles, I took it off the street and raced it like that for 2 seasons. Won lots of races with it. :smile22:

The 3.73 gears are not much different than the 3.90's. And your tires are probably shorter than mine were. So, I think the Muncie will work just fine. :yes
 

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I had a close ratio (2.20) with a 3.42 gear, and if it wasn't for having a 455 with tons of low end, it would have been a dog off the line. But it actually wasn't too bad, for a street car that is. Not the optimum set up for an all out 1/4 mile car, but the car would damn near do a 0-60 all in 1st gear ! When that 2.20 gearbox finally got worn out, I got a wide ratio (2.64) gear box because it was a great price and I needed my car to run as it was my daily driver. I wasn't sure about going with the wide ratio box, but I actually liked it better, and after putting on 29 in. tall Mickey Thompson Sportsman rear tires, my 3.42 was now like a 3.08. But the lower first gear made up for the taller tires from a standing start, and I could cruise on the highway at a lower RPM. So for a street car, I would say the wide ratio box, For a race car, I would choose the close ratio to keep the motor in the curve as the tach won't drop as much on shifts with the close ratio.
 
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