Valve spring question


I have a shop replacing my heads and they were going to put my old (5k miles) valves and springs in to a new set of heads to save me a few bucks. They now call and tell me that while the car was on the dyno that there was an issue at high rpm which they attributed to the valve springs being worn or "short" as they put it.
My question is this: Wouldn't a reputable shop have tested the springs before putting them in the new heads and wouldn't they have noticed they were short? Also how would one be able to tell the springs are short while they are installed on the head under pressure which is mounted to the block?
Thanks.
Last edited by Munch; Jul 27, 2009 at 04:38 PM. Reason: Got answers from my shop.


