About an hour ago I cranked my truck to just let it run for about 15-20 mins. Turned it off and came back out to crank it to run to the store and it will not crank... Everything turns on, lights radio etc but it doesn't want to turn over. I was thinking it was possibly the battery so I tried to give it a jump and it still doesn't want to turn over.. any ideas on where I should start?

 

It could be vapor lock, the long time malady that occurs after the vehicle is turned off, then when it's attempted to be restarted in a short time, it won't start.

This was a common problem for many years, some people wrapped the fuel line from the pump to the carb with aluminum foil or placed wooden clothes pins on the fuel line.

 

Battery, battery cables, ground connections, starter relay, starter, or ignition switch. Could be any one or a combination of these things.

 

Automatic? Cycle the gearshift lever... NSS could be outta whack.

 

2X Number Dummys comments. Could very well be vapor lock. I had the gas boiling in my 2V 390 each time I shut it off. I changed out the metal carb spacer with a phenolic one(and got rid of the carb hot water system) and installed some insulation (Mr. Gasket) on the fuel line from the pump to carb. No more problems.

 

Hwklien88 said the engine would not crank/turn over. If so, fuel delivery won't matter if the engine won't spin. If the description is accurate, the problem points towards an electrical/electrical component issue.

 

Since you are already working on the wiring for the later model T/S switch, I'm thinking it is a wiring issue under the dash. Check to see if you didn't accidentally bump or disconnect wires in the ignition and start circuits. In one of your PMs to me you mentioned the PO hacked the wiring. You might have bumped one of those hack jobs.