Adjusting valves on the ZZ430

[Steves32]

I've had this car about 3 months now. Motor is #416. Prev owner said he had just changed the oil a month before I bought it.
When I dumped the oil- it seemed pretty thick to me. I swapped it for 5w30 Mobil1, motor has about 15,000 miles on it.
While I know these motors are notoriously noisy in the valve train, it seems so much louder now. Loud at idle, Seems to get real loud above 2500 rpm.
So- I think I need to pull the cast valve covers & take a look see.

What is recommended pre-load & procedure? My other car has a solid roller & it's lots quieter than this.

I also have cases of 10w50 Red Line I run in the 55. I wonder if that oil would be quieter?

My oil pressure is great BTW