First use of the Thompson PS pump actually goes back to 1965. In '65 and '66, the metal reservoir housing had a large diameter filler neck. In '67, the filler neck was greatly reduced in size and this is when it got the nick name 'pencil neck' pump and was produced through 1977.

1965/'66 Thompson PS pump w/large diameter filler neck.





1967-1977 Thompson 'pencil neck' PS pump.

 

Old thread, but yes that extra hole is for the cooler. I am running the frame mounted serpentine style on mine that came from the 75 donor. My 85 chassis has a loop on the crossmember. I had an 84 F250 4x4 that I lifted with a straight axle swap and 35s, then drove cross country. The power steering cooler got a bag wrapped around it about an hour into the trip and I lost power steering about two hours later. Six days of freeway driving towing a trailer with oversized tires and no p/s is not fun.

 

C7TZ3C511D:
67/70 F100/250....4X2.....360/390
69/70 F350.........8 cylinder.
71/72 F100/350....360/390.....With power pack.