I got my ClockWork Racing modded JL today. Hoping to do some shake down runs on Thursday. Temps here are supposed to go up to 40*f. My engine came with hand fitted piston and sleeve so really no break-in is required. I will take it easy for the first couple of tanks to make sure everything is good.Neal at Clockwork is very professional and a great person to talk to. I got my engine very fast for anyone worried about shipping from Canada to US.