my best sugestion on the engine, is i know you are sending it off to get bored to a new piston size, but when you get it back it is impairitive that you check to make sure your intake/exhaust ports have been shambered down (filed) if they are not shambered correctly your piston rings will nic them every single tdc/bdc stroke and eventually destroy them and from there your cylinder will lose all compression then be worthless. also when you put your piston rings on the piston, there is and up and a down for both rings. it is important to get those correct. make sure you use the correct tightening pattern and torque on your head bolts. and good luck