360 Advice Needed - Autocross / Street Engine Build

Remember the OP intends to use factory 360 log manifolds so that will definitely influence the cam choice... I don't see a built 360 with log manifolds being able to make power at 6000 RPM but that's just me. I understand the reliability and stock-looking aspect but with a fully built engine like you're planning the log manifolds will be a HUGE choke point and will seriously reduce power and efficiency unless the cam timing is set up for it; if I were you I would get a custom-grind camshaft.