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

[Billy Nees]

Originally Posted by SSDiv6

Billy, there is a lot more in camshaft design and in the early days, it was mostly hit/miss. Camshaft technology has taken great leaps with the advent of computer modeling.



The big difference on the new generation Cheater camshaft is they have faster ramps with bigger numbers in 0.200" lift area.

I agree with you completely that with the advent of "CAD" camshafts there have been great strides in "Stocker" performance potential BUT it is still at a cost! 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. It still comes down to a compromise. When and where ever you increase the speed of the valve event you have to have a spring rate that will allow it to follow the lobe. So you will STILL need better lifters, pushrods, springs etc. to get the job done. And you still have to spin the motor accordingly.