[afterburn 549]

Originally Posted by asphaltgambler

I would first have the bores checked by a good machine shop to establish where that measurement is. You will have to hone to break the glaze so that adds (very slightly) to the existing diameter. I have found that most late model EVO cylinders wear very little under normal conditions so you may be in luck. If the bores are true (round) and in spec then you would source the new pistons and do trial fitment and measuring. Unless you have all the specialty micrometers you may want to leave this to a good machine shop.

If you have to bore the cylinders, they need to done by someone who has a torque plate and experienced with air-cooled cylinder boring. Next there is no factory plating or coating on the cylinder walls like Porsche or BMW. They use a high ductile steel liners.

I'm not sure where you're located but there is shop in Elkridge Maryland called "Zippers Performance" I have personally dealt with them over the last 20 years and they are one of the best HD performance shops out there. Downside to them is they are doing less machine shop services these days and concentrating more on fuel injection development. Check their interweb-site out for parts, services and contact them directly for any further questions. Hope this helps you.

Next question for the brain trust-
On a evo with their combustion design (stock) sense I am going twin plug...what is the best guess the highest C.R. I could get away with for the street with higher lift more over lap cam ?
Looks like 10.5 to 1 is pretty common...........