Before you get overly excited, that trans (yes I have one) may not be what you think it is; It's not like Muncie close ratio.
In the Mopar Close Ratio, the desirable part happens on the 3-4 shift, which with the 3.91s (what it will take to get that Dart Sport moving), top of third gear is ; 5500=84 mph. So I mean, how often are you gonna be up there? and
Still with 3.91s; 5500 in First is about 46 mph, on the 1-2 shift the rpm will fall to .76 x 5500=4200 which is a great Second gear but is it worth running 3.91s and 65mph=3200?
The 3.09 trans will give you the same 10ish to 1 starter gear, but 65=2615, and 46 mph in Second gear is 3535, so yur engine-build is gonna be a lil different for absolute performance, as in forget about a 292 cam.
Here are the Mopar ratios; first yours, then the standard, then the Commando. and beside them are the splits. Third column is the rear gear required to get a decent starter gear of just over-around 10 to 1.
2.47-1.77-1.34-1.00 = = .73-.76-.75 = = 3.91/4.11
2.66-1.92-1.40-1.00 = = .72-.73-.71 = = 3.73
3.09-1.91-1.39-1.00 = = .62-.72-.72 = = 3.23
Happy HotRodding
