----More Q & A from the www.slantsix.org website----
Q: Which is the best ratio 833 4-speed to use in my Slant Six car?
A: It depends on the parts combo you have and what you plan to do with the car. Here is a general overview on how I use the different ratio Chrysler 833 4-speeds:
The OD 833 unit is good for a general purpose street car where you
want good off the line (3.09 first) and great highway cruising. (.73
overdrive) I feel these OD units work best with a 3.91 rear end ratio
but I bet the new 3.73 ratio offered by Randy's R&P would be a
good ratio when used with the OD 4-speed.
(with the 3.73 rear end ratio: 11.53 start-off ratio, 2.72 final drive - OD)
The 3.09 - 1 to 1 final 833 is a good "street / strip" tranny for
a Slant Six. Highway cruise starts to suffer with this gear box. Rear
end ratio of 3.23 is about as low as I can stand on the highway. I
usually run a 2.94 behind this box and put up with the somewhat
"lazy" 9.08 start-off ratio that results.
(with the 3.23 rear end ratio: 9.98 start-off ratio, 3.23 final drive - 1 to 1)
The close ratio (2.66 first) tranny is not a good choice for a
street slant. These are great for racers, 1/4 mile or road course.
You need to run a 3.91 rear to get a 10.40 start-off ratio. (that new
3.73 ratio now offered gives a 9.94 start-off) but these low rear end
ratios suck on the open road. (suck gas and "ring" your ears) The
"super-close ratio" 2.47 "TA box" is even worse when it come to
getting the car to move from a standing start.
Here are the start-off ratio calculations: (2.47 x 3.91 = 9.65 start-off ratio) and (2.47 x 3.55 = 8.77 . . .)
Note: as a general "rule of thumb" a 10 to 1 start-off ratio is pretty good for a "street - strip" Slant Six