Can i install 31's or 33's on my 97 f150 with my 3.55 rears???

 

Yes, but how it affects your drivability depends on the rest of your powertrain.

 

well i am running a stock 5 speed manual trans with OD ready to install a stage 2 clutch and flywheel with pressure plate. but 5th gear at about 70- 75 the truck is screaming, and 1st gear is so short or quick. will that help me gain top end speed and how bad do u think my low end will be affected

(I am looking at the 7.5" fabtech lift and possible 33's or 31's )

 

What engine do you have?

 

7.5" of lift and only 31 or even 33" tires will look bad on even a stock 2wd.

Don't worry about your 2500rpm on the highway. Both the 4.2L and 4.6L like that. What kind of gas mileage do you get? Are you trying to improve it by reducing engine speed @ highway or think the engien will last longer? Is it too loud? What are you trying to accomplish with taller tires?

 

Well i feel like the truck is screaming at 70 mph in 5th gear i keep loking down thinking i am in 4th but im not, so i really want my 5th gear a little longer. It almost feels OD is noy working.

With the taller tires i just want to know if my 4.6L V8 5 speed OD trans w/ 3.55 gears will be ok with those tires or will it not be a good idea to use them cause they are to tall?

why do u think a 7.5" lift will look bad? just cause the height?

Thanks
Ryan

 

I think 33's will look fine with that lift. You may find yourself wanted to install lower gears if you go with 35's.

 

A stock suspension 4x4 97-07 F-150 looks good with 33" tires. Adding 7.5" of lift will look bad to most people because the tires look small compared to that height. Even a 2wd would look poor with 33" tires and 7.5" of lift IMHO because there is only about 3" of height difference between stock 2wd and 4wd.

Any gain in effective gear reduction you get by going to larger tires will be offset by the heavier tire. The manual has a relatively short overdirve, only 0.80:1 compared to the automatic's 0.70:1.

I have 33" tires on my stock suspension 4wd F-150. @ 70mph, I turn under 2000rpm. I wish I could turn 2500RPM with the weight of my truck and tires @ 75mph. I think I'd actually get better fuel economy instead of unlocking my torque converter on any incline.

Really, 2500rpm @ 75mph is not a big deal. Check out the towing forums where people tow in 3rd gear on automatics (1.00:1 gear) @ 3000rpm for hours at a time under heavier loads. This engien design (Triton V8s 4.6L and 5.4L) are happy in the 2500-3000rpm range. I wouldn't worry about the "screaming engine" unless the enhaust is too loud.