I hooked up, both wires. Saw some diagrams showing 3 wires, I'll check it out this weekend.
There are three studs on some Delco starters but only two of the three are used on the CK trucks after 1974 or 1975.
The 3/8" BAT stud is obviously the battery and one or two fusible links depending on the year.
The other two studs are machine screw threads.
The #8 stud is for the crank wire from the neutral safety or clutch interlock switch. It may be marked S.
The #10 Stud provides full voltage to the coil when the starter is being cranked. It may sometimes be marked R or I. It's only used on the breaker point ignition systems.
If the ring terminal on the crank wire is original or the replacement is for the correct stud diameter, you can't hook the starter studs up incorrectly.
You're using 16ga wire to connect 10ga wires. The Delphi 8911698 double hole terminal was roughly equivalent to 10ga. That's not the main issue but it may become a problem eventually if you draw too much current. The right way to do that is to use a chunk of copper bar. If you want to go ghetto just use a flattened piece of copper tube with 1/4" and 3/16" holes to slide over the studs. The other option is to move all of the wires to one of the two studs.
No power in the cab will be the fusible link at the starter.
Slow crank is usually the battery cables or battery cable terminations. Loose or corroded ground on the alternator bracket or battery. Loose or corroded connections on the positive cable to the starter or battery. Or the battery cable(s) are internally corroded... Or a hammered starter.