ramjam

hey all, with my 1991 f150 xlt lariat with 5.8 351W, regular cab long bed, 4x4, e4od transmission, lifted with 33" tires. does any one know where i can get all factory specs? as in gear ratio in rear end, horse power, torque. just all of the specs. thank you.

khasse

look at the axle tag on the rear diff cover for the ratio.

horsepower and torque: 1991 5.8W (351 ci) 210 hp @ 3800 rpm 315 ft/lb @ 2800 rpm MPFI

if you need anything else just ask.

ramjam

so im guessing they did different axles? the guy before me that i got the truck from did a new dif cover and there is no tag he tok it off

mitchalvin

With no tag you will have to pull the cover off and count the teeth to get the exact ratio, you can mark the ring gear and the drive shaft and then rotate the ring gear one revolution while counting the number of revolution that the drive line makes. This will give you a fairly good approximation to the ratio. Some gear sets are stamped with the ratio or the tooth count for the ring and pinion gears.

Nitehawkjr

Or you can get the axle code off the plate on the door jam if it's the original rear end. Or you can mark the drive shaft and the wheel and count the revolutions of the shaft to one revolution of the tire, that will give you a close idea of what you have.