engine speed for best fuel economy?

[MUDKICKR]

4x4TruckinGirl you have 3.55s

 

[Diesel JD]

If it was 3.55s with 37" tires it would be closer to 1500-1600 RPM at 65mph, I could be wrong though.

 

[Shadetreemechanic]

If it was 3.55s with 37" tires it would be closer to 1500-1600 RPM at 65mph, I could be wrong though.

I think you are making the assumption that the speedo has been corrected.

 

[Diesel JD]

Very true I am assuming that, and perhaps(probably) I should not.

 

[4x4TruckinGirl]

I seriously doubt that the speedo has been calibrated.... it also jumps around a lot, same with the tach, but I know when it's reading correct and when it's not..... I guess from my understanding thats an RPM sensor that will fix this issue.... one day I'll get around to that...... also, I didn't forget the pics, just didn't get a chance to today, but its on my priorities tomorrow.

 

[RKOCH]

A ZF5 is also an overdrive that lowers RPM quite a bit. Personally I have a C6 in all my rigs. I hate overdrive. I perfer power. So with a 4.10 gear @ 3000 rpm pushing 12 PSI boost with 38.5 inch swampers. I just figured my milage @ 14 mpg.

 

[MUDKICKR]

nope on 92 -96 ford trks you have to take it to the dealer to have the speedo reprogramed, or get an aftermarket speedo programmer

 

[Mike]

nope on 92 -96 ford trks you have to take it to the dealer to have the speedo reprogramed, or get an aftermarket speedo programmer

Not true.....

Article here.