[boyt911sc]

Don't worry about the drilling even if you drilled more than 1.5". It won't go any further because you'll be hitting the cylinder head 8 mm stud. All you need is a threaded hole of 1/2" to 3/4". The cavity (threaded hole) is just about 3/4" deep. Your concern about producing metal shavings going inside the engine will not happen (valve covers installed) even if you try to do it!!!!!!

Tony