408 LA build

You only need a good step or two bigger cam to hit your goals. If you know your valve to piston clearance, retainer to guide/seal clearance and spring specs, and rocker ratio you could see how much lobe lift you “could” fit, then call around. But just throwing out something, even with your gearing, for what you’re looking for I’d be mighty tempted to try something with specs similar to, with a little wider LSA or even actually this:

Drag Race Solid Flat Tappet Cam - Chrysler 273-360 278/278