Yup me too..I broke the fins on my first 7 port head and I had broken 2 fins on the new gen 5 I just killed too..I do have a spare undamaged 7 port head but if you fit the cooling fin back into place carefully and use little JB weld(the 24hr stuff not the rapid) between the fins next to the core it fixes em pretty good..I broke fins on RB novarossi and os motors before so it's not just a GO problem..main thing to be sure of is enough clearance between your body shell and the fins...when you flip the car upside down the body gets a fair whack and will easily break fins if it touches em..same as the lexan will cut off your exhast stinger if you don't leave enough clearance..