I understand that you don't want to run springs that exactly match the lift on your cam but what's the limit on how much over? Random example: Cam has .580 lift, would a spring rated .600 be too much? How about a spring rated for .625? Just a question that's been on my mind since I'm going to be building my engine soon.

 

I think your example of .580 with a spring rated @.600 would be right at the limit.

 

The valve spring term you will be looking for is "coil bind". You should not have your valve lift get less than .060" from coil bind. Some people do run closer but for most that is a good number to go by.

Going by your example if a spring is rated at .600" lift that would take the coil bind into account and all would be good. However you will need to check the installed height of your spring to match the rating of the spring that you choose.

 

Thank you sir

 

Basicaly look at the right pessues to match the lobe requirement