I have a 390 in mine with a C6 automatic.
Here's the engine:
My 74 F-100 was my first vehicle. I've had her for 15 years now and have put over 10k in her. They are well worth the time and money. I know my truck inside and out, so if you need any help with it let me know. My next project on her is putting in a 4-speed toploader, and those aluminum Edelbrock heads.
Here's the pickup and my 03 Mach 1:
Here's some specs on my engine:
TRW Forged pistons .30 over with cobra lemans rods.
Ford SVO cam 524 intake 524 exhaust, 292 duration
Offenhauser 360 degree dual plane intake
670 CFM Race Demon carb (It's a holley street avenger in the pic)
Ford OEM electronic ignition