Neal wrote:I can't remember the exact difference between the two but you can use either one on a stock bike . As allways , check the squish before you start it . You can still use the stock br ecm plug with the rear head swap - i never had a problem with doing it .

Ok that's cool. Could you point me towards a how-to on measuring squish accurately? There isn't much that I could see in the top end rebuild section on the site. Don't want to get it wrong.