i have a 89 f-150 with ttb and i was wondering if a solid axle swap if worth it, if i did a swap i was planning a 8" lift with 3" body, but if i keep the TTB i would do a 6" lift with 3" body for arond $1,700.  Does any one know which is worth doing for the money?  

It depends on what you plan on doing with the truck.  Your front TTB is likely the Dana 44 model.  This means that your truck would take 35 inch tires with a 4 inch lift (a little fender trimming may be required).  I wouldn't go larger than 35s though because then you'll be asking for breakage (if you plan on wheeling it somewhat hard).  The thing about the TTB is that proper alignment is key.  It also isn't quite as flexy as a solid axle would be.  You would also want to swap in different gears (4.10s or 4.56s) to take away some of the stress from the larger tires, and improve overall driveability.

If you plan to swap (say a solid Dana 44), tire and lift size would be the same story except for that the front would require more custom fab on your part.

You really don't need all of that extra lift of an 8 inch or the 3 inch body to fit the 35s which would be the largest tire size to go with with those two axles.  If you wanted to swap front and rear with Dana 60s, then you could go with more lift to fit larger tires.

Thanks,  

 I ahve 250 acres up in New Hampshire and i ride atvs, dirtbikes, tractors, backhoes, dozers, i know the land very much there is a lot on steep inclines and declines to my trails. Im tring to level them out as much as i can but it will take a while.  While the 4 inch lift allow me to be able to attemp these trails?

im not going to be jumping or beating on my truck. I just want it to be able to take it out wiht my family and friends and wheel in some small mud holes, and jsut have some fun.

Sure, it sounds like 35's (or 33's) and a 4 inch would work great for you.  I ran a four inch and 35 inch BFGs on a 90 f-250 and had no rubbing, although you may require some fender trimming with your half-ton.  One thing you should do is change your gears, unless youre already running 4.10s, to either 4.10s or 4.56s.  I was young and stupid when i had my f-250 and could never figure out why it ran so bad.  It was because I was running 3.73 gears with 35s!  Another thing you should do since you plan on wheeling is make sure you get rear leaf springs, not lift blocks.  Other than that, I can't think of anything else

Thanks for the information about the gears,  I would never go wiht the blocks, the trucks sits lot as it is, im putting a 3" body lift on it first.  I have to get a new transmittion first , and prob redo the motor so its dependable and the bod lift because it will allow me to try out the truck to see how it does driveing.   Im going to be taking it easy on this truck until i find something older that is carborated and has solid axles front and rear.