Does running with the body on affect carb tune?

[GJB56]

I believe I have my carb tuned pretty good. I kill it on a WOT run and the plug is paper bag brown. When I put on the body it runs okay for a few minutes then starts to get sluggish before it just stops and won't start. I change the plug and run again without the body and she runs great. My thoughts are less air flow with the body on? Does this sound normal to anyone?

 

[RampageHopUps]

No, there is enough airlfow around the wheel wells, that it shouldn't matter.