Called Arrow and shot the [censored] with them for a bit.

This engine cost 27k. Uses stock rockers. The alternator on these nascar type engines cost 2k. They are running titanium valves that are coated on stock seats. They drill an .025 hole in exhaust shaft to spray oil on exhaust valves all the time. These engines make around 480hp with a 390 carb and a plate with i think he said 1 1/16ths holes. Will make over 600hp with a 750 carb.

He said they use stock rockers and apache valves in the trans am series. Never broke a valve but said on a spintron the intake valve starts losing control over 7000 rpm. They primarily run a PSI 1511 in everything and change them often but said they never broke a stock apache valve