Why did nhra change the cam and valve spring rule in 1985?

[Rick Leininger Jr.]

Originally Posted by Billy Nees

No matter where you increase the opening and closing rates on the cam the valve MUST follow the ramp and the rate of opening or closing.

IF you use the ceramic lifters.

[SSDiv6]

Originally Posted by Rick Leininger Jr.

IF you use the ceramic lifters.

Yep...in the past I have addressed the subject of valve train dynamics and camshaft lobes in the Tech section...there is a lot more on new camshaft designs that do not require the high spring pressures being used today...