70 duster project

I’m always open to suggestions, I have a basic understanding of how it all works, but haven’t built alot of engines. I’d like to break 400 hp with the 340. I’ve been looking at the thumper cam. 295/312 advertised .507/.494 lift thought that would be more fitting with 2.02/ 1.60 valves, may have to look into some different gears but I haven’t bought them yet either. Just thought the 3.55s were a happy medium
What’s the overall goal of the car? Just a hood streeter it seems like.
3.55’s are everyday performance street gears. I run them in my car, the wife’s and my sons truck, all 360 powered.
(If there back by an overdrive, there really good.)

If your using the flow masters for there sound, OK fine but I’d would run a DynoMax or Summits turbo muffler, (best turbo muffler) or a Hooker Aerochamber, best Chambered muffler and awesome sound or a straight through Hooker or Dynomax “Maxflow” muffler. Glass pack ish style.