1965 4 speed

[Darryl D.]

Was the 1965 4 speed a close or wide ratio?

[Stewart L.]

Re: 1965 4 speed

A wide ratio was used with all base and L75 engines. All others used a close ratio.

[Darryl D.]

Re: 1965 4 speed

A wide ratio was used with all base and L75 engines. All others used a close ratio.

I did not realize they used both in 1965. I know you could order your choice in 1966. So, in 1965 the factory decided for you depending on what engine you ordered?

[Jim D.]

Re: 1965 4 speed

I did not realize they used both in 1965. I know you could order your choice in 1966. So, in 1965 the factory decided for you depending on what engine you ordered?

That is correct, but I also believe the rear ratio chosen was considered in that decision.

[Richard G.]

Re: 1965 4 speed

1963 was the same, with both wide and close ratio transmissions depending on the motor.

My 340HP came with optional 4.11 but would have been standard with 3.73's.
Sometime in the first five years the 4;11's were replaced with 3.55's
Bet the low gears got really old on the highway. About the same time my car came from the Midwest to the West Coast.
Possibly the gear change was made in prep for the trip?
It is a little long in first gear with the 3.55's and the close ratio. Likely would have been slightly easier to drive with the 3.73 ratio.

In 1963 the 250hp and 300hp came out with a

3.08:1

and the

Wide-Ratio 4-Speed

In 1963 the 340hp and 360hp came out with a

3.73:1

and the

Close-Ratio 4-Speed

Lets do the math for both transmissions with the standard rear gears;
Muncie M20 that has a 2.52 first gear ratio with a Standard 3.08 rear axle gear ratio. Our combined first gear ratio would be [3.08 x 2.52 = 7.76]
Muncie M21 that has a 2.20 first gear ratio with a Standard 3.73 rear axle gear ratio. Our combined first gear ratio would be [3.73 x 2.20 = 7.81]
Just not a lot of difference in first gear.

Wide Ratio M20 Close Ratio M21 Rear ratio 4.11 3.73 3.55 3.08 4.11 3.73 3.55 3.08 1St gear 2.52 2.52 2.52 2.52 2.20 2.20 2.20 2.20 Total ratio 10.36 9.4 8.946 7.762 9.042 8.206 7.81 6.776
Rick

[Darryl D.]

Re: 1965 4 speed

1963 was the same, with both wide and close ratio transmissions depending on the motor.

My 340HP came with optional 4.11 but would have been standard with 3.73's.
Sometime in the first five years the 4;11's were replaced with 3.55's
Bet the low gears got really old on the highway. About the same time my car came from the Midwest to the West Coast.
Possibly the gear change was made in prep for the trip?
It is a little long in first gear with the 3.55's and the close ratio. Likely would have been slightly easier to drive with the 3.73 ratio.

In 1963 the 250hp and 300hp came out with a

3.08:1

and the

Wide-Ratio 4-Speed

In 1963 the 340hp and 360hp came out with a

3.73:1

and the

Close-Ratio 4-Speed

Lets do the math for both transmissions with the standard rear gears;
Muncie M20 that has a 2.52 first gear ratio with a Standard 3.08 rear axle gear ratio. Our combined first gear ratio would be [3.08 x 2.52 = 7.76]
Muncie M21 that has a 2.20 first gear ratio with a Standard 3.73 rear axle gear ratio. Our combined first gear ratio would be [3.73 x 2.20 = 7.81]
Just not a lot of difference in first gear.

Wide Ratio M20 Close Ratio M21 Rear ratio 4.11 3.73 3.55 3.08 4.11 3.73 3.55 3.08 1St gear 2.52 2.52 2.52 2.52 2.20 2.20 2.20 2.20 Total ratio 10.36 9.4 8.946 7.762 9.042 8.206 7.81 6.776
Rick

For 1965 I believe some of your above information is incorrect. The standard rear end ratio in 1965 was a 3.36 gear. The 308 was an optional highway gear. Also they didn’t start using 3.73 until later and used a 3.70 instead.

[Gene M.]

Re: 1965 4 speed

I seem to recall 3.55 gear was the break off for wide ratio.

So a wide ratio 3.55 had the equal in first gear to 4.11 with close ratio. And ya could actually cruise on the highway at 75 or 80 MPH with out screaming the engine.

[Willard M.]

Re: 1965 4 speed

I know that I'm a psychologist and not a mechanic but wide or close ration should not make any difference once in fourth gear. That is a 1:1 ratio and depends just on what rear end ratio you have. Am I correct?

[Michael J.]

Re: 1965 4 speed

I know that I'm a psychologist and not a mechanic but wide or close ration should not make any difference once in fourth gear. That is a 1:1 ratio and depends just on what rear end ratio you have. Am I correct?

Correct, and the same goes for a three speed or Powerglide, final gear is 1:1.

[Gene M.]

Re: 1965 4 speed

I know that I'm a psychologist and not a mechanic but wide or close ration should not make any difference once in fourth gear. That is a 1:1 ratio and depends just on what rear end ratio you have. Am I correct?

Yes, the rear end ratio determines the engine RPM in 4 th gear. Lower gears 4.11, 3.73 higher RPM vs 3.08, 3.36, 3.55. That is why in todays world the wide ratio with say 3.55 gear would driver daily with less engine RPM’s on the highway and still get fast starts off the line.