65 barracuda Commando 273 /Formula S?
Looks like someone has been playing with that cuda some already. The rear is not original it looks like an 8.75 or ford 9 inch? as I had my 66 set up with one when I raced it. They originally had very small 7.25 small bolt pattern rears with 13 inch rims. Mt 65 now has a 8.25 with big bolt pattern so I can use 14 inch ralley wheels. You can also get custom motor mounts to give some more space in engine bay for headders but it means modification to hood as motor will be too tall. It is all up to your imagination. I hAve seen a few early cudas with 340's that look very nice and run well. You have a good start. Loose the single master cylinder and convert to double for saftey it is one of the first things I did on both of mine as it is easy to go fast but way harder to stop these cool old beasts! Keep posting picts we love the picts!
Very nice truck by the way!!!!