Couple of 360/5.9l questions?

I figured the direction I want to go over the next 5+ years with my car 68 Valiant stock body & interior, I'm keeping it small block want to eventually go high to mid 11's want no roll bar or cage. Want decent streetability be able to go anywhere at anytime.

Looking to make peak power around 6500 rpm, right now it's got a 380hp crate engine 2800 stall and 2.94 gears. But 1st I want go backwards and start with stock cam, china air gap and headers then gear for maximum 1/4 mile and go from there, mod to mod until mid 11s.

Even though I got low mileage engine I want to build a zero deck LA roller block with forged 3.31/3.58/3.79 crank haven't decided yet to swap in at some point.

Questions

1 Can a magnum 5.9l be drilled for LA rocker oiling ?

2 Are crank spacers safe on a 450-500 hp to 7000 ish rpms?

3 How much hp needed to do mid 11s in a 3500 lbs car on drag radials? but with no /6 bars or drag racing leafs. Do have fully adjustable shocks.