[magwakeenercew2jh]

I always have to offer this disclaimer: I'm no mechanic. Just a dude that (sometimes) thinks logically.
But, I DO I know how to "trace wires" and "R&R parts". Hahahaha!!!!

I'm thinking that if the truck sat for a while, I'd even be MORE suspicious of the water pump.

To, me, all this work and NOT replace a water pump? Probably a mistake. Have you checked the price of
a water pump for a 350? Sixty bucks at Summit....Maybe even better from a Forum Seller....In all, pretty cheap insurance...

Maybe a little pricey for diagnosing a problem. But "what the hay"? In the end, you have a new water pump.