suggestions for my 340?

Intake wise, a Stealth or RPM
Carb 750 cfm, Holley or Edelbrock
Headers from Summit racing $150
Summit racing exhaust $223 for a 2-1/2 system with mufflers
A complete cam kit, not just cam and lifters but the whole deal done right is about a tick over a grand.
Just a cam and lifter and spring set is about $460 give or take.