If your going to go with the DOHC head, might as well slap the turbo in with it. I have the same year you have with a SOHC and made some changes for low end torque that I needed. There is quite a few things you can do to these motors and stay in a reasonable budget. Carb, header, cam, distributor curve, machine work to intake and head. Droppedmitsu has a great thread about replacing head to DOHC and adding turbo. My thread has some stuff on the SOHC improvements and there are many more thread builds here that can point you in any direction you like. You can find most in the Gen 1 / Gen 2 forum threads. Check your pricing for anything you plan to do for more horsepower. Parts for these trucks can be hard to find sometimes and can start to add up cash quickly. Dropping a V6 or V8 in compare to improving a 4 cylinder come very close to each other in cost. Parts for an American motor and trany can be found a little easier also and cost a hell of a lot less in most cases.