I have a 2002 club cab. It was built with a 3.9 motor. I am getting ready to do an engine swap. I am putting in a 440 with a 727 torqueflite. I am not sure what gear I should go with for the rear end. I am thinking of going with a 4.10. I want something that will preform and still keep the rpms down on the highway when traveling out of state. Also can I get away with just changing the gears or should I find a rear end? If I need to get a rear end what would bolt in with out having to mod the hangers etc.

 

What rear end do you have now? Is it the 8.25 (10 bolt cover) or 9.25 (12 bolt cover)? Both were available.

You can just swap the gears.

 

4.10 for the engine may be to low unless all you plan on doing is off-roading for any highway driving that would suck.

Just my opinion everyone likes something different

 

I would think that a 4.10 would give you a screaming engine at highway speeds. Are you after stoplight drags or power and highway cruising? Higher numbers also mean higher engine speed at higher road speed. A slower turning engine will scream less, but for that you need a lower numerical number in the rear.

And if you change the ratio, remember that the speedo will be off proportionately too. A 4.10 will show you traveling at 60 when you are only going say 55 or less.

Man a 440 in a Dakota! Zounds!!!

 

Remember guys, the torqueflite is 3 speeds, with a 1.0:1 final. There's no overrdrive as in the later model transmissions - although an "overdrive" unit was available.

In comparison the 46RE has a 0.69:1 final ratio.

Some quick calculations with 31" tires and a 4.10 differential:

At 65 mph with 1:1 ratio you'd be turning 2889 rpm. (Torqueflite in 3rd)
At 65 mph with a .69:1 ratio you'd be turning 1993 rpm. (46RE in 4th).

 

really depends on what the main use of the truck will be, a daily driver will want a lower cruise but sacrifice in other areas, racing you want the numerically higher gear to get you off the line, but you will be high rpm at highway speeds

 

With a 440, I can't imagine you would have any trouble pulling a 3.54 gear, and that would keep your RPM reasonable. 4.10 is too low, IMO.

 

Depends on size of tires you are gonna run. 4.10 is gonna be too high. Will be fine running 3.55's