Well, after many hours of working on my heads during my lunch breaks and some finish work this weekend in my garage I am nearly finished porting and polishing the exhaust ports on my head.

Its hard to get a good photo of the improvement in shape, size and finish, but if you look at the untouched intake ports it gives you a good idea of what I started with.

Once I finish boring out the intake port inlets they will be getting the same treatment.

 

sa-weeet.

 

Nice. I love that, separate heads for each cylinder, and look, you can see out the exhaust port looking straight down into the bowl. Very nice.

And those intake ports are pretty bad. I've seen worse, DSM heads have some pretty bad casting flaws at times, but on a Porsche? You should see nice gains from that porting.

 

I finally had a chance to bore out one of my intake ports on the mill yesterday. One down, five to go. At least I know what I will be up to during my lunch breaks all this week.

As the pics show my bore angle calculations were dead on the mark. To properly mate up with the larger part of the port the hole is bored 3.2 degrees towards the combustion chamber.

The new port size is now 39.5 mm.

There is still a little blending to do but the end of my headwork is near.

As the marker shows the area near the injector port will be a little narrow so I will probably add some epoxy to that area for a little extra safetey margin.

The most hair raising part of this operation is that the reamed out intake port comes within 0.09" of the valve spring seat.

So far so good at least.