I'm putting a 383 in a 1988 dodge Dakota two wheel drive! I used the bottom of oil pan from 3.9 an joined it w the 383 pan !! How can I lower the rack an pinion w out messing anything up! Any input would be great

You cant really.. not without messing things up..
as the body changes location it would either toe
in or out.. I assume you have a the A-arm upper and
lower arms.. if you lower every thing by the same amount
it would work(upper and lower inner pivot points)... if
its a strut just drop the lower A-arm pivots the same
amount)
EDIT
The thing is you want to keep the outer tie rod
ends level with the rack.. if you drop the rack
a 1/2" you could put some shims at the outer tie
rod to equal it..thats about the only way

If you lower the rack, at the minimum you must make sure what ever change is made in location to the inner tie rod end is duplicated on the outer tie rod end. Go the absolute minimum you need, and double check bump steer when you get it mocked up. Moving the outer tie rod end upsets the relationship to the spindle, and bumpsteer problems can occur if you go very far, and by that I mean fractions of an inch. What happens is as the camber changes, the further you move that tie rod end out by the spindle the more the camber change will change the toe as it moves through its travel.
Find a direct connection Chassis Book and study the chapter on front suspension. Then graph it out. You can use two pieces of 1/2 square tubing about 28 inches long. Use bungee cords to strap them to the wheels about six to eight inches off the ground. Level them. Hook tape measures to the ends and record the toe difference as you raise or lower the vehicle. To allow the front suspension to move unhindered, two sheets of tin under the tires with oil in between will allow the front tires to move sideways as needed.