Edelbrock LD340 Intake Manifold Usable Max RPM?

I shift at 6300-6400 and cross the strip at 6800 with a massaged stock 340 intake. Your intake is better. For cam, I would talk to a reputable cam company and tell the exactly what you are doing. As an example, we share a somewhat similar intake, but you don’t want my cam specs. I run exhaust manifolds to your headers. I run a bunch of lobe separation.