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