So I now have 2 Arrow .21 engines. 1 in a Agama buggy using 30% nitro 11% oil Byrons, 7.0 Carb Insert, and silver + copper head shims. Using a Jammin JP3 tuned pipe.

I have another Arrow in a Hot Bodies D8T, 30% nitro 11% oil Byrons, 8.0 Carb Insert, and silver + copper head shims. Using a Precirotate MP1 tuned pipe.

Both engines have a little over a gallon in them. SHOULD I LOSE ANY OF THE HEAD SHIMS? WHAT ARE YOUR THOUGHTS ON THE CARB INSERTS?

Thanks ahead of time for your help with this.