Rear End Questions

[My7d1]

I just bought a 72 Blazer 4x4 with a stock 350, a 4speed and the 3.73 rear. I have a rebuilt 2.73 rear that was going to go in my 71 C-10 with a 250 but with that 350 I am thinking the 2.73 will be way better on gas mileage, my questions are:

1. Will the 2.73 affect the torque?
2. I assume it will so the pick up at a light will be slower, noticeably? Not looking to race just keep up with traffic, get off road in the mountains and in snow (which is going to require highway driving) AND get decent gas mileage.
3. Anything I should be cautious of doing the swap?
4. Assume something will need to be done with speedometer?

Appreciate any input/advice offered.

[bigrigpardo]

1 you need a 2.73 front or your 4wd wont work.
2 with the 2.73 you may need to use 4lo when off roading to compensate
3 a 2wd rear wont fit in a 4wd because the perches are farther apart

[imjeff]

Do you have a 2:73 front as well? How tall of a tire are you running. That gear will definitely affect your off the line as well as pick up running around. Your clutch will probably bear the brunt of it. I can't imagine you'd get enough improved mileage to make up for the burnt clutches and new front end gear. These trucks just aren't mileage monsters, regardless of gear. I really like the 3:73 and have ran that gear in just about every 4wd I've had. As to the speedometer, there are gears available to calibrate. I generally do that after I put the tire size I'm going to run on the truck since that affects gearing as well.

[My7d1]

Really appreciate the info, looks like the 3.73 is staying where she is! The seller says he is only getting about 10 mpg, any suggestions to bump it to 15 or maybe better? I'd even look at changing the 4 speed out if needed...

[truckster]

Originally Posted by My7d1

Really appreciate the info, looks like the 3.73 is staying where she is! The seller says he is only getting about 10 mpg, any suggestions to bump it to 15 or maybe better? I'd even look at changing the 4 speed out if needed...

There's always the LS/4L60E swap option. I'm putting in a Vortec with a Quadrajet and HEI and hope to get in the neighborhood of 15; an LS should do better.

It's mighty good of the seller to be honest about his fuel mileage. A lot of folks fudge the truth when it comes time to sell.

[My7d1]

Originally Posted by truckster

There's always the LS/4L60E swap option. I'm putting in a Vortec with a Quadrajet and HEI and hope to get in the neighborhood of 15; an LS should do better.

It's mighty good of the seller to be honest about his fuel mileage. A lot of folks fudge the truth when it comes time to sell.

He's a good guy giving it a good home, at least in my opinion... I will start looking into the LS/4L60E swap, this is going to be a fun project...