Sorry for the previous pictures. I went to a hobby shop this afternoon with the engine asking about the crack I noticed where the exhaust header attaches too. It is a crack as the shop employee pointed out & he said that I shouldn't worry about it. I have looked at Traxxas engines on ebay and other rc cars for sale which include an engine, as rc car engines at the hobby shops where I live are out of stock. I hope this helps.
Thanks