I generally use a normal spanner on prop shaft flanges but on occasion I've used a torque spanner with a crow's foot extension- you need to measure the extra length of the crow's foot and adjust the torque setting down to compensate.
Is the tank venting properly ? Open the cap and see if things improve.
Maybe the run heated the fuel so much it's boiling in the pump suction line. In this case it will improve when the tank cools down.
Where is the pressure gauge tapping? The gauge is not showing 108 psi.
OK. Could be heat soak from the block to the coolant -the 10 min delay is a characteristic of this cause-this has happened to me occasionally on 40+C deg days in an old V8 Holden after a few hours running at high speed. These days if this is likely to happen I idle the engine for 5 mins or so after stopping to cool things down.