Inliners International Forums General Discussion Drive Train 2 Groove 3 Speed or 4 Speed?

Hi All,

This question is for a mild street modified 77 Camaro with a 250,that when completed in this iteration will have 160-175 HP. Will be a near stock power band. Dumped the integrated head. It has a 2.73 rear end but I have a 3.08 available. Stock 14 in wheels and tires, have not measured tire height.

I have a both 2 groove 3 speed and 2 groove 4 speed (3.11 first) Saginaw transmissions.

I can do the math and see how the 2 transmission would do on paper but I am reaching out to see if anyone has real world experience with the the wide ratios of the 3 speeds vs the closer ratios of the 4 speeds and the power band of the inlines. Which one works better with the inlines? Specifically the 250 and curious about the 292.

Thank,
Rick

The closer you can keep the ratios the less the rpms will drop between shifts, and will keep the motor in a better power band. I hope this makes sense to you.

Hi Larry,

I understand your point. My question, regarding mine as described (peak torque rpm about stock) ...is that with the wider ratio of the 3 speed, that the larger RPM drop would take advantage of where stock torque lives?

Thanks Again,
Rick

The wide ratios in the 3 speed have a simple reason: to make the 1st gear high enough numerically to move the vehicle from dead stop with a tall axle. If they were closer you'd kill the clutch in traffic.
A 3.11:1 4-speed (Saginaw?) is a better choice.

I also feel the 4 speed is better with either of the rearends you have. Some simple math is that you will reach the torque range four times instead of three with smaller steps in between. The 3.11 low will get you going. Your long stroke six will keep you going.

A wide ratio trans would be my choice. Close ratio trans offer advantages for peaky, narrow power band race engines. Inlines generally have a flat(ish) torque curve, so you won't fall out of its power band easily.

40 years ago I had a Camaro with a 250, 2.20 Muncie close ratio, and even with a 3.70 axle (at 8.14:1 crawl ratio fails the "10:1" test) it was misery to drive in traffic.

Swapped the manual for a TH350 with Vega converter, much happier.

Hi All,

This may end up a dupe. I hit submit and the window disappeared but I did not see the post. - - -

I am humbled by the level of experts that responded to my post. I truly appreciate your time, especially during the holidays.

I wanted to throw one more thing out there. The gear ratios of the 2 transmissions and the drop between gears. There is a 10% difference in drop between the 2 transmissions.

3.11 - 2.20 - 1.47 - 1.0
29.26% 33.18% 31.96%

3.11 - 1.84 - 1.0
40.83% 45.65%

Merry Christmas/Happy Holidays to you and yours.

Regards,
Rick

I'm going to toss my 2 cents in and say more the merrier.
Having driven a 194 with Powerglide tranny for years, don't underestimate having a gear to down shift to going up hills or passing.
The 250 and 292 was a lot better with the TH350. (3.08 rear)
The 250 with wide ratio Muncie 4 speed was fun too. (3.36 rear)
Faster in 1/4 mile? 60 foot times?
Don't know, just more fun to drive.

Less fun: Interstates! If anyone talks about overdrive trannys listen.
Good luck with your project.

Thanks to all...

Based on the feedback and numerical calculations. The 4 speed it is.

Happy New Year!

Regards,
Rick