What can be said about the 4-speed New Process NV833 overdrive manual transmission?

[hatzie]

I ran a 1985 305 with an SM465 and 2.73:1 rear gears. She ran around 11-12mpg in town and 14-15mpg highway. She was a dog too.

If you're after highway mileage I'd lean toward the A833 with shorter rear gears like the 4.11:1 set. That was a very common ratio so you may already have them.

The original 1966 pickup truck axle came with 3.07:1, 3.73:1, and 4.11:1 gears The ElCamino could be had with 3.36:1 gears. 4.11:1 was listed as "overdrive only" the taller, lower number, ratios were used with regular gearboxes.

GM New Process A833 NP440 MY6 MM7 overdrive transmission ratios.
1st 3.09 2nd 1.67 3rd 1.00 4th 0.73

Assuming you are running metric tires close to the original 1966 C10 size 205/75R15 tires.
You can shift MPH to RPMs by several hundred RPMs just by changing tire sizes.

65mph in 0.73:1 4th gear 205/75R15 tires and 4.11:1 gears would be turning roughly 2400 RPM.
Launching might be a bit more difficult. 5MPH is 787 RPM...

You can do a bunch of what-if calculations in my spreadsheet.
The red numbers are transmission ratios. For 5th & 6th gears just enter 0.00 The RPM to MPH tables will re-calculate when you change the red and blue numbers.
The blue numbers can be edited for tire size and other items.
http://www.mediafire.com/download/zk...ansferCase.zip