this only happens when i am on it hard. does not do it when just cruising around. is it my timing or something else?

 

you have a lean condition..

 

So, could be timing (should be around 13BTDC or so for spirited use) or dirty fuel injectors or something. Not really a big problem, but throw some TL-3 injector cleaner in there or some STP fuel system clean out to try and fix it up along with checking the timing.

 

BG PRODUCTS make some awsum fuel injector cleaner like 15 bucks a can it works!