the fitting on top the tank is the sending unit, looks
like this inside [plus the float and a 'sock' on the end of the tube] ... can't recall which side it points to, but unless your tank is virtually empty you won't be able to get the truck high enough any direction to do what you propose, remember the pickup is designed to use
all the gas in the tank going uphill or down, it almost sits on the bottom
to avoid siphoning too much, disconnect the fitting at the tank first, then have a small container under the connection at the pump to catch what's still in the line .... done
Bill