Overheating 360 new engine

I wouldn't go down the timing route with the sniper, yet. The sniper will only allow you to change the advance at idle and at specific breakpoints. While a nice feature to have, you've already proven that timing isn't your issue (you advanced it yourself).

Back to the fans. Those two fans aren't covering the surface area of the radiator, so my bet is that those are the culprit of the overheating. Your pulley ratio looks good. Crank is larger than water pump.

How much room from wp pulley to radiator?