I had a customer that wanted his head ported and polished while we had it off for an o-ringing. This is a head off a 5.9 24 valve Cummins Diesel. I don't know exactly how much power gains we get from these, but it has to help flow more air. Here are some pics of the head and the work I've done to it.

Stock



Starting



Stock Exhaust side



Starting Porting Exhaust Ports