Mainly stock rebuild Including KB 400 pistons, 69 RR cam, comp 911 valve springs. Stock rebuild 906 heads. No block decking or head milling. The noise is not to bad, just thinking it should be quiter.
I don't think I would run anything other than stock. If I remember right, I THINK the 383 HP came with the HD stock type rockers that MP later offered. They had a thicker cross section at the pushrod cup area and were beefier everywhere else too. Those should be all you need.
As for the noise, you probably need to do some inspecting. It should be pretty quiet.
I bet that makes for a nice combo though. GREAT street motor.
