C1 3 to 4 speed conversion

[Michael Jones]

I am going to convert my '57 from the 3-speed Saginaw tranny to a 4-speed, probably a Muncie. Is a Muncie the correct choice? I'm running the stock 245hp dual quad setup.

My 3-speed has the 2.20 1st gear running with a 3.70 rear end. It lugs a little off the line but is adequate. Which gear set should I use in the Muncie: the close ratio with 2.20 or the wide ratio with 2.54 1st.

And finally what is such a swap out likely to cost?

Michael

[Jack H.]

Re: C1 3 to 4 speed conversion

Muncie is known to be much more durable than early Borg T-10 (AND a lot easier on the wallet). A close ratio Muncie will be a bit more pricey than an 'ordinary' wide ratio and you'll see no appreciable difference in 1st gear 'lugging'. However, with wide ratio you won't be able to dwell in 1st gear as long while RPMs climb.

Have close ratio in my BB and the engine's native torque is more than sufficient to compensate for off the line start up. Have wide ratio in my SB with 3.36 rear end and no problemas. Have known several with high rev, solid lifter SB's who complained of 'stumbling' with close ratio, changed to wide ratio and were HAPPY with the net results....

[Verle R.]

Re: C1 3 to 4 speed conversion

Michael,

I replaced the stock Borg Warner in my 57 with a Muncie for driving. That way, if I should miss a shift it is not a catastrophy.

I chose a wide ratio (2.56 first gear) so it would be more compatible with my high gear rearend for better highway cruising.

You will need the adapter plate for the rear mount and the long yoke for the driveshaft. When I bought them, they were about $15. and $120 respectivly.

I recommend a Hurst shifter but you can make a stock Borg Warner 4-speed shifter work on the Muncie.

A wide ratio Muncie will cost anywhere from $250 to $600, depending on who you buy from. If you know someone who knows something about Muncies, take them to a swap meet and begin your search.

Good luck,

Verle

[Joe Pennington]

Re: C1 3 to 4 speed conversion

I have the wide ratio Muncie with a 3.36 rear gear behind the 265 CuIn, 210HP and don't have problems with 1st gear stumbling. Total 1st gear ratio is 8.60. A close ratio with a 3.70 rear has a total 1st gear ratio of 8.14. A wide ratio Muncie with a 3.70 rear gear gives you a total 1st gear ratio of 9.47.

[Doug Flaten]

Re: C1 3 to 4 speed conversion

I second Jack's response about a Wide ratio. I had a Close ratio Muncie in my 270 h.p., and if was great if you wanted to scream up to 70 mph in 1st gear. However, It was a little doggy in first gear and my wife's Delta 88 could beat it off the line. I switched to a wide ration and it is much more pleasant to drive in town.