This 1965 F100 belongs to Dennis Austin (Dennis.Austinusdoj.gov):

This is the '65 I have been working on. Not much mechanically is left on this truck that is original. Its my $600.00 truck.
I am going to say it a modified 302 V8... vintage unknown.
It has headers, Edelbrock Performer 289 Manifold, Carburator, & Breather.
Chrome dress up kit.
NP435 from a '77
Front end rebuilt from new parts with disc brakes for a '74.
Rear end out of a '74.
Bucket seats from an import.

It has enough power to easily spin those big rear tires in second gear. I use it to cruise around in and make trips to Home Depot. Needs A/C here in this 100 degree weather.