Hi Denny,

Don't know the exact specs for this cam but judging by the duration and lsa I would be very surprised if there were anything left much over 6000. With a very generous 100% VE that puts you at 705cfm for a 406. Say you pull to 6500 you're at 760 with the same unlikely 100%. Do you disagree AFR has nothing to do with CFM? Why go lean at the top?

Anyway depends what you're doing with the car... If you're racing put the 850 on there and have fun... 750 is plenty big enough for virtually anything you want to do and you'll still have some throttle response. IMO 750 will be plenty even on the strip.

-Chris