[Steve C.]

From the OP....

"For reference this is a combo street/road race application 468. Certainly not a race engine at under 600 hp but a hydraulic roller lifter will be stressed in this form of racing."

Not mentioned, he has intentions for boost with this application. And as mentioned a road race application at extended RPMs.

For discussion.....

"Consider the fact that when the engine is in a "boosted" condition, the supercharger (or turbocharger) is trying to blow the intake valve open. The boost pressure actually reduces the intake valve spring seat pressure. This is extremely critical on engines with hydraulic lash adjustment."

https://www.yellowbullet.com/threads...essure.239727/
\

Now, if you plan on pushing a lot of boost into your engine, things get a little more complicated when it comes to valve spring pressures.

“In a boosted application with very high boost numbers, you should take into consideration that the backside of the inlet valve is under constant static pressure, which does indeed diminish the seat pressure."

https://www.dragzine.com/tech-storie...ring-pressure/


.