Questions

[Lonestar10]

Driving across i-80 Nebraska today doin 72 no wind flatland and this pig is sitting between 25 to 30 psi. In my experience at Crete my cascadia would be at 7-10psi and a '14 387 with 500hp paccar would be at 12-15psi at 80mph 90k lbs of grain on this route.

So basically what can be costing me so much power. 200k on overhaul, head as far I know is original 1.1mil has all new parts besides valves/springs. Cams 200k, turbo 150k, everything new in the fuel system besides the gear pump and regulators, cams wedged at 4.5, mm2ed, stock programming previously, virgin 13sp, 3.36s turning into 3.70s Friday, uses 1gal in 15k, overhead good, EGR blocked

Issues

two davco fuel filters for oil change - asphaltine

Tapping noise under load like a ball peen on a solid piece of metal cant identify for the life of me. Jake brake rockers seem to be good.

2 exhaust valve seals leaking oil

So could it be valves?
.5 degree to much timing?
Gears really costing me that much?
Idk any ideas?