I built and dyno tested a stroker 440 bracket motor for a customer two yrs. ago that he wanted to run low tens in a 1965 Belvedere 1 street car on race gas. I put a sold roller cam and the valve springs recommended by the cam grinder with 325 lbs. on the seats and 840 lbs. opened, that motor got the oil hot in a hurry shock
Andy, are you seeing that in your testing with similar spring pressures?

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)