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. on the stainless flanges please email me to go over availability and quantity orders. i can do a lower cost if a quantity order is done on the stainless flanges.