I have an 88 F150 with a 5.0 and i want to put a lift and stick some 35' tires under it. I was wondering how much of a lift i need to do that. Also out of curiosity more than caring how much will that affect my gas mileage i get average 17 MPG right now with 265's on it?

 

You will need atleast a 7" lift if you still want some good clearance thats what I have. 8" would be a better lift. Depends on what tires you go with. Street tires will get you better gas milage then mud tires. I would say expect 10-12 at the worse.

 

First of all, you're going to need to recalibrate the PSOM to know the true effect on your mileage. Otherwise, your mileage is REALLY going to suck, because the odo's not going to turn nearly as much with the larger tires. Bigger tires = fewer revolutions per mile = lower axel speed = lower speed/distance measurement for same distance traveled. There's a procedure in here somewhere for recalibrating the PSOM, though, and it doesn't look difficult.

Secondly, with a 5.0, you'll need to consider a gear change for taller tires. Do you have any idea what ratio the dif(s) is (are)? I say that with plurality if you have a 4x4. With a 4x4, if you change ratio in one, you better change ratio in the other. Otherwise, you're going to have some really interesting problems in the transfer case or the weaker diff.

Thirdly, with the taller tires, if you don't reduce gear ratio, your low end power which is already a little on the wimpy side (I have a 5.0L too, in front of a 3.08 diff) is really going to suffer. It might look better, but it'll be a dog to drive if it's geared too high for the big tires. Fuel mileage is probably still going to suffer from having to stay in lower gears longer. A little more info about the tranny and diff is needed here.

I'm sticking with the stock look, because my 4x2 looks just fine (o me) with the 255-75's x 15's on it. I like my chrome factory wheels just fine. So, I have no idea how much lift you're gonna need.

(EDIT): I just realized you said '88 model. I think those used a mechanical speedo/odo and cable drive. Forget what I said about the PSOM. Gonna need a different drive gear for the speedo.