I had to modify my intake manifold to accept the 60mm B18 throttle body I wanted to install. I first traced around the B18 gasket just to give me some idea of where I needed to remove material. This mark also helped me keep the bore in a pirfect circle. After all the material was removed I cleaned the bore up with a 80grit, then 120 grit sand paper flap wheel. While I was at it I also cleaned up the intake runners with a small grinding bit and a flap wheel.

{gallery}techstuff/intakeporting{/gallery}