A good flowing NA head will work good with a turbo. BUT......A turbo engine loves volume. Search some of my posts and I have posted pics of how they look. The Buick V6 head has a VERY biased intake port, and needs to have the back side of the valve guide radiused away from the port long side. Pay close attention to a good three angle valve job, and keep the lower angle at .100". The short side needs a good radius and needs to be as wide as possible. The valve guide (int.) needs to be narrowed/shaped significantly. You can completely remove the valve guide in the exhaust port. There is water pretty close in the exhaust bowl, so be careful. Core shift will determine how far you should port. You can grind ALOT of material out of the entire ports. Do not remove the lump on the short turn radius(intake port), just gradually smooth it out. It is there for a reason, but it is a bit much from the faactory. Leave a nice bull nose on the inlet edge of the intake guide and be SURE to radius the back side of the intake guide on the biased side of the port. (long side) Some head porters miss that and leave alot on the table. (IMO) The intake port can be taken out to a 1200 Flepro intake gasket, but you will have to install brass tubes in the push rod holes. (just epoxy them in) The head bolt holes can be enlarged and sleeved too, with the port wall taken out to them. I would leave the ports smaller than that unless you are trying to get every little bit out of your heads. You can have the EGR ports filled or even welded. I used steel drill rod to fill the holes and have seen them filled with aluminum, too. The two end EGR ports can be filled with a 1/4" cap screw (allen head) installed from the intake flange of the head. You will need an extended tap to cut the threads, though. Have a good valve job done before you port the heads, and just leave a .125" bottom width and then port the bowls out to that dimension. Expect to spend over 10 hours on a set of heads IF you know what you are doing, and have good carbide and die grinders. You will probably HATE doing it by the time you are done. If $1250 won't kill you, I would HIGHLY suggest buying a professionally ported set. I don't hink you can make the heads any worse than they currently are, unless you break through into water. A turbo will cover LOTS of mistakes. Good luck and I encourage you to have at it. You will at least understand why ported heads cost what they do. It AIN'T easy.
