Transmission Gear Ratio?

[Dodge68charger]

What Sort Of First Gear Ratio Should I Run In My 4 Speed Transmission. The Car Has 3:73 Gears In The Rear End And Goin Behind a 454

Also Whats a Fair Price For a Used An M-21. Thanks

[57Suburb]

2.95:1

[Quikshft]

Originally Posted by Dodge68charger

What Sort Of First Gear Ratio Should I Run In My 4 Speed Transmission. The Car Has 3:73 Gears In The Rear End And Goin Behind a 454

Also Whats a Fair Price For a Used An M-21. Thanks

I like shifting close ratio gears. Is this a car it is going into? If so with a 3.73 rear I'd pick a 2.20 first gear.

[Dodge68charger]

Originally Posted by Quikshft

I like shifting close ratio gears. Is this a car it is going into? If so with a 3.73 rear I'd pick a 2.20 first gear.

Posted via Mobile Device

My Wifes 71 chevelle

[weq92f]

.
I think 2.66:1 w/3.42 is perfect...My rough translation of that into your project yields 2.35:1, which is pretty close to Quickshift's 2.20:1.

-klb

[Mts67C10K20]

Let's not forget to take tire dia and weight of the car into consideration
Monza to Monte carlo can make a big difference

[Mike C]

IMO, nothing could be a worse choice than an M21/M22. The 2.20 first gear absolutely stinks with less than a 4.56 gear. The 2.66 first and 3.42 is getting closer.

I had a 2.62 first Super T10 in my Camaro and thought it was the 2.44. I broke it and replaced it with the 2.44 and miss the 2.62. And that's with a 4.10 gear.

In my big block Corvette I bought a McLeod street 5 speeed which has same ratios as a T5 from a V8 Camaro. 2.95 first and a .64 OD. I'll be running 3.73 in the rear which is right at an 11:1 first gear which is my preference on the street.

[weim55]

Originally Posted by Mike C

IMO, nothing could be a worse choice than an M21/M22. The 2.20 first gear absolutely stinks with less than a 4.56 gear. The 2.66 first and 3.42 is getting closer.

I had a 2.62 first Super T10 in my Camaro and thought it was the 2.44. I broke it and replaced it with the 2.44 and miss the 2.62. And that's with a 4.10 gear.

In my big block Corvette I bought a McLeod street 5 speeed which has same ratios as a T5 from a V8 Camaro. 2.95 first and a .64 OD. I'll be running 3.73 in the rear which is right at an 11:1 first gear which is my preference on the street.

This.

All real ( and very rare) M21s are a 2.20 first and just miserable to live with and less you have a 4.56 or numerically higher axle ratio. All factory GM Muncie M 20s have a 2.52 first Which is much better. My favorite with your combination of Big block torque and 3.73s would be a 2.66 first super T 10 box. Close enough ratios to be fun running through gears on the street but a low enough first gear to get out of the hole. If you’re going to be drag racing with slicks a lot nothing lower numerically than a 3.00. It’s been a while since I’ve priced a good rebuilt Muncie or T 10 but I’m guessing probably 700 to 1000?

Steve weim55 Colorado

[Steeveedee]

I had a '64 Impala convertible with a SHP 327 and a close ratio Muncie (2.20 1st gear) and even with a 3.90 axle, it was a total pig off the line. With a posi and a 10-inch clutch, it would smoke the clutch before it broke the tires loose. It broke 3rd gear for some reason, and I went back stock, but I really regretted not putting the 2.61 cluster and first gear in it. I had put in a 3-speed temporarily while waiting for parts for the original trans, and that 2.61 low was a real launch animal, even with that convertible's weight. Given that your truck is about the same weight, you might consider the wide-ratio trans.