Is it worth changing gears for better MPG's???

[93GMCSierra]

just a couple of questions, I have a 5 sp manual trans the shifter was labeled
L 1 2 3 OD
However I can drive in OD at 23 mph with out lugging an even have some torque on acceleration an at 65 mph my tach is about 26-2700 RPM. When really pushing the truck I hit 90 mph at 4000 which is were it seems to have a rev limiter, which is good as I was not intending to blow the motor.
Now my questions are this, why do my RPM's seem alot higher then others with the same set up?
Oh an when I got the truck it had stock sized tires, 245/75/16 steel rims, now has 265/75/16's still steel rims.
My speedo has not been corrected however the difference between its mark an a traffic radar checker is at most 2 mph at 45 mph

[TurboDiverArt]

just a couple of questions, I have a 5 sp manual trans the shifter was labeled
L 1 2 3 OD
However I can drive in OD at 23 mph with out lugging an even have some torque on acceleration an at 65 mph my tach is about 26-2700 RPM. When really pushing the truck I hit 90 mph at 4000 which is were it seems to have a rev limiter, which is good as I was not intending to blow the motor.
Now my questions are this, why do my RPM's seem alot higher then others with the same set up?
Oh an when I got the truck it had stock sized tires, 245/75/16 steel rims, now has 265/75/16's still steel rims.
My speedo has not been corrected however the difference between its mark an a traffic radar checker is at most 2 mph at 45 mph

What kind of gears do you have in the rear? It's either steep gears or your tach is off. 4000 RPM's seems pretty high. My engine has pretty much quit at 3500.

Art.

[93GMCSierra]

What kind of gears do you have in the rear? It's either steep gears or your tach is off. 4000 RPM's seems pretty high. My engine has pretty much quit at 3500.

Art.

I have not had the opportunity to find out yet, nor which transmission it is. Or is there only 1 5 spd they put in these trucks?

[JohnC]

There was only one trans in '93 for the 6.5. Don't know if the 6.2 was the same or not. Chances are your alternator was swaped and has the wrong pulley. This throws the tach off. 4000 RPM is above the governor set point.

[93GMCSierra]

Has anyone ever replaced the stock 5 spd with a 6 spd?

[6.5 Detroit Diesel]

I know a few people who have swapped the trannys. The Dodge trucks have the NV5600's which is the 6-speed. I think one of the biggest things would be finding out if the bellhousing from the 4500 will bolt onto the 5600.