Stephen,

This will depend on what year the truck is. Need last letter of serial number. If this has MSTS ignition, there is a connector near the MAP sensor that has a jumper in it, three pin amp connector. Remove connector and check timing at front pulley. It should read 0 degrees. If not, need to adjust. For the older units, there is a single connector that is for timing next to the distributor on the right side when looking at it. Disconnect the wire and again, timing should read 0 degree. Let me know if you need additional info. Remember to connect timing light to number one cylinder which is closest to the radiator. Good Luck.