That’s quiet a cam for a 340, if you wanted to add some compression, a good single plane intake and some gears to wind it up I’d say it would run good.
I ran a older Hughes fs in my 408. The cam was 260/264 @ .050 with .62?/.64? lift IIRC. The engine had ported Edelbrocks that flowed in the mid 290’s, 10.8-1. It ran 6.57 @ 104 shifting at 6400 in a 3260# 69 Dart.
I ran the same heads on a 340 with a Hughes hydraulic, 237/242 @ .050, the lift was a little under .600”. It was 11.4-1 and ran 7.24 @ 94 and change in the Dart. Also shifter at 6400,I tried more and less rpm’s with both engines and 6400 was what they liked.
Call Porter and pick his brain on the cam, he won’t steer you wrong.