6 plugs and the motorcraft wires should be fine.
Stick with either Motorcraft, Autolite, NGK or Denso Irisium plugs. Do NOT get Bosch no matter how good the deal is. 99.9% of the time Bosch plugs will make the motor run rough.
Get a spark plug gap tool and make sure you gap the plugs to 0.054".
Before you change the wires label them and replace one at a time so you don't mix up the order.
The order of the cylinders when looking from the front of the motor is (left hand side is passenger side) 1, 2, 3. (right hand side is drivers side) 4,5,6.
On the coilpack make sure you connect the wires right, the order is 123 465, yeah 465, it looks strange but lots of ppl make that mistake.
Also to get at the #3 plug, the pass side one closest to the firewall, you'll need some sockets with universal elbows or you need to jack up the truck, take the pass side front tire off and come at the plug through the wheel well.
You may want to put a dab of anit-seize compound on the plug threads before you install them, makes it easier to take them out later.
Get yourself either a Hayne's or Chilton's repair manual for the step by step on most repairs.
97 XL 4.2L V6 Reg Cab Std Box 4r70w 3.73 TruTrac LS, General Grabber UHP 265/70R16s, Line-x spray-in bedliner, Truxedo Deuce tonneau, 20% tint, AF1 CAI, ASP UDP, Magnaflow catback SIDO, Magnaflow Hiflow Cats, Port & Polish 1/2 shaft TB, Troyer tuned.
Whaddya mean I don't pay my bills??
Whyddya think I'm broke!!
163.17 rwhp 231.59 rwtq (94 tune)