Got my PKMM d-ports
 

I got a great deal on a set of KRE 310cfm cnc ported d-ports awhile ago. But after getting them i wasnt too impressed with the port work done by the cnc and the exhaust port in general i wasnt crazy about. So i gave them to Pual K to clean up the intakes and get the exhaust where i wanted it. He managed to increase the average flow by 20cfm on the intake and 25cfm on the exhaust. Thats a pretty good average increase from .100 to .700. Our Grand Prix will be getting these, it'll be interesting to see how the preformance changes vs our 240cfm iron d-ports.

Are you going to swap heads with no other changes? Same cr?

Would be an interesting test for sure.

That was the plan, but not sure now.

Good stuff.

So they flow in the 330 range now?

Not quite. The 310cfm advertised was only 290cfm. They flow 325cfm now.

Would definitely like to know how this swap works out. Thinking about doing the same thing on Curtis' Bird. How much performance increase with just a head swap? Probably have to richin' up the jetting.

I'm no expert but if staying at the same compression ratio, wont it lose a little due to the heat characteristics of aluminum. Ive always thought you need to bump up a little comp.
when going to aluminum from iron

In theory but theory isn't reality. Hot Rod magazine did a great back to back test on a sbc with identical heads from dart except iron vs alum. Their finding was no difference between the two.

Increased flow probably offset the compression "loss" with the al. head.

The Engine Masters TV show tested identical port aluminum vs iron heads and if anything the aluminum made more power down low and both were identical at the peak. Another one of those old hot rodder myths busted.

There was no flow difference

Maybe this is the one.
https://www.hotrod.com/articles/ccrp...er-heads-test/

Does the manufacture and type of flow bench used make a difference in reported numbers ?

KRE at one time did not use a SuperFlow test bench on their cylinder heads. Unless they changed types. Years ago it was a J.K.M. flow bench. The JKM uses an averaging velocity tube to measure flow.
I also know David Vizard when he tested a cylinder head for me it was a Quadrant Scientific Flowlab 520 bench at the time. It was a laminar flow orifices. Both are different methods.


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In this case Paul flowed head before and after porting so it's a good comparison of the gains

Paul does nice work!

Before or after ?
 

The port pics are they before or after ?
And are they gasket matched ?

The pics are after Paul ported them. Intake port is whatever size KRE makes them for their 310cfm port. Exhaust side is matched to gasket.

This is the advertised intake gasket...

TIP-120230
1.20 x 2.30 openings .060 thick
These gaskets are used on 310 cfm KRE D ports and as cast KRE High Ports


https://tinindianperformance.com/pon...%20gaskets.htm





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Mm . . . I measure the width on the intake side of my KRE D-ports that are gasket matched to Felpro 90205 I get 27.5 mm ( 1.08") and I already ran into the pushrod hole twice.
In the picture the bridge between the ports doesn't seem to have lost any material so going an extra 3mm. (0.12") on the pushrod side , i would think this would certainly cause problems ?

In the pics I can see that the valvecover bolt hole is also been broken into.

On both my 295cfm and 300 cfm SD ported D-ports the valve cover hole is open. I use studs with sealer for my valve covers