The Porting Process

I definitely wanted to port my heads. It's about the only thing left to do with these already-modified cast iron heads. They've got three-coil valvesprings, screw-in studs, guideplates, 1.6" roller rockers, Comp Cams hardened pushrods, and undercut stainless steel valves. I spent a few hours and cut the exhaust ports and bowls open a little bit wider. The intake ports on these heads are pretty much perfect from the factory, but I did however trim all of the casting flaws away and removed imperfections for slightly better flow.

Vortec heads prior to modifying them. I laid the old exhaust gasket over the exhaust ports. Look how much material I can remove just to gasket match the ports! It's around 1/4-3/8" of an inch total diameter.
       
One ported, seven more to go. This is approximately .150" of material removed. Not only that, but the inside of the port is also contoured much better and all casting flaws have been taken out as well. Just a picture of me grinding away slowly with a dull bit on these ports!
       
This is pretty much what I was trying to accomplish. After porting, I did a 3-angle valve job on all 16 of the seats. Not only does this help to increase flow, but it also keeps compression up.