[BLAZERMAN]

There is a way you can test with a vacuum guage but I dont know how reliable that is. To test them right they have to be removed and in that case you might as well replace them anyway...good thing is you can do this without removing the heads. Did lunati suggest a stiffer spring? with a healthy cam you should always replace them anyway..espicially on a motor your not sure about. Did you hear this motor run before doing this work? Weak valve springs usually show up at higher RPMs but with a new high lift cam on an old motor they can show up right off idle. Hopefully someone else on here that know big blocks better than me will chime in.