I have a 3.55 ratio rear-end in my '68 Camaro. The car has the original 327 v8. I would like to install a 4 speed but am a little confused on the gear ratios offered in these. What would work well for a street driven car-no racing? I am looking for a ratio that would work well with the 3.55 rear gear. Also, does anyone have any opinions on a Saginaw 4-speed? I know they are heavier with the cast iron case than a muncie or Borg Warner. Thanks for any help given on this topic!

Do a search under my handle for this b/c I have posted it before.

3-speeds and 4-speeds.

pdq67

Sorry PDQ67, I didn't find the info I am looking for. Anyone else have any comments? Thanks!

I looked in my Chevelle Restoration Guide (can't find my Camaro Guide, but assume the ratios are the same, since they stuck M20's and M21's in Camaros as well) and it lists the following:

Muncie M20

1st 2.56 to 1
2nd 1.91 to 1
3rd 1.48 to 1
4th 1.0 to 1

M21/M22

1st 2.22 to 1
2nd 1.64 to 1
3rd 1.28 to 1
4th 1.0 to 1

I don't know about the saginaw or Borg Warner trans. With a 3.55 either one of the muncies is not a bad choice if your car is just a cruiser around town. On the highway you will be cranking your Engine RPM's a bit at 70 mph. Go to the Keisler Trans web site and you can compare Engine RPM's between a 4 spd and one of their 5/6 speeds (or at least you used too, I haven't been there in a while). I think the Richmond Gear website used to do that as well.

I had a 3.31 geared 396 Chevelle with a M20 muncie. It was great except out on the freeway. 75 mph meant I was at over 3000 RPM so my mileage pretty much sucked, but I was pretty much in the power band all the time so that was fun. It is all in what you want. With a 3.55 you could go with a 5 spd overdrive and have the best of both worlds.

Posted here by me on Mar 21st, 05, 03:09 PM a while back!! "Saginaw or Not Saginaw 4 Speed" post................................

http://www.camaros.net/forums/showthread.php?t=50814

"Here's how you ID a Saginaw 4-speed trans.

4 speed Saginaws
no lines= 2.84-2.01-1.34-1.00
1 line= 2.54-1.80-1.44-1.00 common
1 Line= 2.54-1.80-1.32-1.00 rare
2 Lines= 3.11-2.20-1.47-1.00
3 Lines= 3.50-2.46-1.65-1.00

And, imho, the rare, 2.54 tranny would live the longest behind a good motor! And next, the common 2.54 tranny... Next, the 2.84 followed by the 3.11 and last the 3.50...

And I figure you will shell a 3.50 tranny in a heartbeat if you HOOK!"

pdq67

PS., what's wrong with the search deal??

I'm currently running an M-21 in my Nova with a 3.90 rear gear.
Even with the 3.90, that 2.20 first gear is a little high. I do like the close ratio between third, and fourth gear that you don't get with the M-20.
If I'm not mistaken, you could get either the M-20, or M-21 with the 3.55 rear gear. Personally, I wouldn't run an M-21 with less than 3.73s.
With the 3.55s, I think you would be happier with the 2.54 first gear in the M-20. There's a bigger rpm drop from 3 - 4, but a lot better low end grunt in first. The rpm drop is about the same as the M-21 in the first three gears, it's fourth gear that you'll see the bigger rpm drop. Not a big deal on a street driven car.
You'll get mixed opinions on the Saginaws...probably ok for a low hp Street only car if you don't abuse it too much. The up side is that you can probably find a nice saginaw for half the price of a Muncie.

I went from a 2.56 1st with a 4.10 rear to a 2.20 first gear and a 3.55 (M22 build). This is with a fairly stout 355. I have to slip the clutch a bit more than I like to get going. In my case, the solution will be a bigger motor this winter! With the 327, I'd suggest the 2.56 first gear. The 3.55 will help keep rpm's civilized on the street. With the 3.55, I cruise at 3K at 60 MPH with a 26" tall tire.