The last time I installed injectors in a 24valve I purchased complete injectors. Now that I am shopping again for another truck I see I can just buy nozzles. What is the proper procedure for the swap onto my injector bodies? Any special tooling required?

 

You will need a vice (and I am not talking about gambling or drinking) the kind that secures objects for work.
A 15mm wrench and or 15mm deep well socket; and a torque wrench.

A piece of small 1/4" square stock metal available at any hardware store.
The square stock metal once secured in the vice will allow you to secure the injectors body from turning.

Hold the injector and untorque the retainer nut with a 15mm wrench or socket. This could take some leverage so you might have someone help you hold the injector or be there for moral support.

Pay attention to how the unit is disassembled and only do one at a time so you are not mixing parts from different injectors.
You can re-use your stock copper washers if you get them off without damaging them. A good way to do this is to use a small knife blade from a swiss army knife to seperate the washer from the tip before untorqueing the tip from the body.

Use a clean well lit environment. Disposable lab mats work very well and are lint free (These can be found at Walmart or the like in the pet section, yeah they have another use )

Upon re-assembly be sure to lube the new injector tip and needed valve. Make sure the assembly stays lined up while re-threading the retainer nut back onto the injector.
Re-assembly and torque the tip to 33-35ft lbs.