I am a Mobil 1 faithful, use it(15W-50) in my 1987 BMW.

The engine in my camaro is about to hit thre 500 mile mark, so it's time to change. what conventional oil should I use for the first 3K miles for this? Would Valvoline VR1 work? In what weight? 20W-50? or would that be too heavy to star with......

I would like to switch over to Mobil 1 15W-50 after that, as it's formulated for high-performance engines, and it's my personal perference and I've always had good expereince with it, in a multitude of different motors

the motor is a 350 block, 400 crank, .030 over. high lift/duration crane cam, hooker headers, ported/polished heads, bigger valves with hardened valve seats, balanced/blueprinted, Air Gap intake, Holley 750 carb. estimated 390+HP