Coming off turnpike onto exit ramp last nite, downshifted to high RPM's and then immediately heard a cylinder missing. At low RPM's there's a CLACK, TAP type sound coming from under the hood.

Had a MTI C2 cam with Manley springs and tit retainers installed just over a month ago...

Looked around and found nothing visibly out of the ordinary. Spring went and dropped a valve? Anyone have other ideas?

 

hopefully you only broke a spring..

 

That sounds like what may have happened. Snapped spring. Check it out soon.