Does it do it in every gear, and does it recover as soon as you shift? Like instantly?
In my experience, valve float typically just feels like a power drop, not like you're hitting a rev limiter (if you know what that feels like, which is a very pronounced stuttering and obvious missing). But it recovers as soon as you shift and get the RPM's back down. A fuel issue can feel the same, or it can be like a sporadic miss, but typically takes a few moments to recover after shifting, if it does recover.
I'd be skeptical of springs that have sat compressed for 10 years, especially if then used on an aggressive lobe like Comp usually has.