You know, I'm not sure on those. The ones I had did have the distributors with the usual wires and such. Yours may have coil packs. If so, I would change the wires and put in either Bosch +4 or +2 plugs or NGK V Power plugs. I have ran V powers for many years and never had a bad plug. They wrok very well. The +4 are relatively new but they burn real clean and lowers emissions. You have a good truck. Nothing like a good ole' Silverado. That engine should last up to 300k or more. Its just a 350 less two pistons. Same bore, stroke and valve train. I have had them and like them. Wouldn't mine having another 4.3 L. Just look towards the back of the engine to see if there is a distributor or not. I wish you well or your tune up. Henry
