I have a 2000 F150 XLT, with 5.4, Flowmaster Exhaust, K&N FIPK, Shift Kit, Diablo Chip. The truck currently has 3:55LS with the stock size tires, 255/70R-16. I would like to stay with the stock tires but install a set of 4:10's. What can I expect in performance, and fuel economy? Any helpful hints or comments would be greatly appreciated. Thank you very much.

 

You can expect better performance and possibly the same fuel economy. The reasoning behind that is thet the truck will increase the torque to the rear wheels and you will require less effort to accelerate. This should offset the few hundred rpm increase at identical speeds over the stock gears.

Regards

Jean Marc Chartier

 

Went from 3.55 to 4.10 with stock 255/16 tires.

Much better low-end and about the same mileage on my 2002 5.4L.

Used the Microtuner to correct the speedometer. Knocked about 1 second of 0-60 times.