[mattfranklin]

Most likely:
Did the season change?
Maybe the carb changes that you focused on

Less likely, but possible, and only an engine geek would appreciate. ;-)
Wilder cam = later intake valve closing.
With that later valve closing pushing more mixture back into the intake, you need to put your foot into it a little more deeply to maintain speed.
You wind up with lower throttling or pumping losses (keywords: Miller and Atkinson, throttling losses, pumping losses).

Or maybe the earlier intake opening gives you a little more exhaust gas puffed back into the mix. (keywords: residual EGR, throttling losses, pumping losses) And you have to put your foot a little deeper into it. And wind up with those decreases in throttling or pumping losses.

Other engine geeks might challenge those comments. We could have lots of good discussion and the only way to settle it would be a really well instrumented engine and careful experiments.