raceland manifold oil return hole
 

fitting my raceland tomorrow...when you tap and plug the oil return hole i had a m10 bolt and the bolt head was too big so i hack sawed it off and hacksawed a little groove on the top so that i can use it as a screw head... but how do i stop the screw/bolt from going all of the way in??? just tap the hole half way or something???? cheers and also how long will it have to be??

any1?????????