CNC Plasma cut in house from half inch thick mild steel or stainless steel. they will come with the bolt holes drilled or cut out. No porting needed, I cut the runners to be a gasket matched fit. 12v and 24v options below. flanges will come with no engraving on the center. If you are wanting to have a custom flange made whether its for a cummins diesel or a different motor, or want to have some engraving done to the flange you ordered please email me.