ok so im looking at a 1983 f 150 with a 9 in skyjacker lift and a 3in body lift with 39.5 super swamper tsl and 4.88 gears and i was wonder if anyone had an idea of what kind of gas mileage it might get? thanks everyone!!

 

Welcome to the FTE, Jordan. Not to rain on your gas mileage parade, but I think 'BAD MPG' comes to mind first. It's probably going to be more like gallons per mile. My stock 351w, 4bbl, C6, 3:50 gears, 31" tires, no lift, just a straight short bed 4x4, gets 12 on a good day. And that is driving it old man style.
It may look cool and impress the hotties and make your buddies drool, but a year ago fuel was $4/gal. Turning those superswampers will require deep pockets.

 

i was thinking of putting superswamper truxes sts on it after i got it and the boy said it wud get 12 to 14 bt i did believe him bt if it will get 12 ill be happy because i had an 06 f150 on 33s and it might have got 14 bt thanks to a drunk lady that truck is totaled now

 

Well, to prove the point (because I think the owner is lying to you). Ask him if you can take the truck for a test drive (no four wheeling, nothing) to the local burger joint 30 miles away...just getting the feel of the thing and you will buy him a burger and shake. Top that tank off beginning and end, with an odometer reading start to finish and it will settle the issue right there.
I guess in the end if the 408 stroker were really a fuel effecient engine, ford would be dropping them into their new production trucks right now. 12 mpg even with smaller tires might be a long stretch. But thats just me. I think someone wants to sell a truck they can't afford to put gas into and knows your interested in it for it's looks, not some surmised 'fuel ecomony'.

 

You will be looking between 7-11mpg.