if i build a BUDGET 360.... LA Vs Magnum 5.9

If the car has been off the road for a long time, there will be way more to address, than a bigger engine.
Brakes, steering, fuel system, lights, wiring etc.
Get the car running and safe to drive down the road, than look into what you want by then. The un-seen stuff will nickel and dime you to death.