That very well could be. At idle ( 525  RPM )  I can hardly tell there is a cam..

Here is a video of mine idling at about 550 rpm and you can for sure hear the cam. i love the sound. Hey also how much fuel pressure are you guys running. My 500 cfm eddy seems to only like bout 4.5 but edelbrock recommended 5.5. 
https://www.facebook.com/ian.goolsby.5/videos/10155189035714338/?pnref=story

Carter/Edelbrock carburetor float levels are sensitive to the fuel pressure.  If the fuel pressure is altered from the time one of those carbs was initially setup, then that will require a fuel float level adjustment in which to compensate.

Lorena, Texas (South of Waco)