also im looking into replacing my old worn out shocks with new ones. would like to add maybe an inch or two to the ride is this possible?
The guys already covered the tach issue, so I'll jump on this - generally shocks do not alter ride height, unless you get special "load-carrier" kind that has either a coil spring or a small air spring built into it. In my experience such shocks do in fact raise the ride height some, but are not too great at providing good ride quality. Which end are you trying to lift anyways, front or rear?
Rear is easy if truck is 2wd, stick a pair of F150 (for 1-1/2" lift) or F250 (for 2-1/2" lift) 4x4 blocks between the springs and the axle. Lifting a 4x4 F350 is best done by altering or replacing the leaf packs as these trucks already have the 4" blocks from the factory and going higher than that is just asking for trouble IMHO (altho Dodge did use some 5" or 6" tall blocks on their 4x4 duallies). As far as brand goes the absolute best IMHO is Bilstein but they ain't cheap, then there is a recent thread on here where Monroe Gas Magnums are also praised.
If it's the front you're wanting to lift a bit, and your truck is a 2wd, then things get interesting - load-carriers (Gabriel makes one like that, #34057 according to AutoZone's website) will do what you want, but you'll have to have the truck realigned, which may or may not work out depending on how she sits right now... Lifting a 4x4 truck in the same manner does not require realigning the front, it's a bolt on and go affair.
