Ported Dart pro 1 pre platinum

[Carnut1]

I was given a very simple job on these heads. Have them beat a cnc head!

Beat a cnc head how?
On the flow bench?
On the dyno?

How will you decide they are/aren't beating a cnc head?
What criteria will be used to determine that?

Randy

Good question Randy, airflow as measured by flowbench.

[Carnut1]

1226160937_HDR.jpg

Dart 200cc ported to 224cc. Port layout and airspeeds at .7" lift and 294.5cfm. Interesting, I should have done this a week ago! Any input is welcome. Thanks, Charlie

[randy331]

I was given a very simple job on these heads. Have them beat a cnc head!

Beat a cnc head how?
On the flow bench?
On the dyno?

How will you decide they are/aren't beating a cnc head?
What criteria will be used to determine that?

Randy

Good question Randy, airflow as measured by flowbench.

That's easy then. Just make it big.

Randy

[Carnut1]

That was the other requirement I may have forgotten to mention, I need an average port velocity of 300ft/sec.

[Frankshaft]

^^^ why?

[Carnut1]

^^^ why?

Good question, airspeed was suggested by party I am doing project for. Thanks, Charlie

[Rick360]

That was the other requirement I may have forgotten to mention, I need an average port velocity of 300ft/sec.

Flowbench velocity of 300ft/sec?

Big ports can still be fast on the bench. Sized for the engine they are going on for good velocity on the running engine at the rpm range used is what matters.

Rick

[Carnut1]

That was the other requirement I may have forgotten to mention, I need an average port velocity of 300ft/sec.

Flowbench velocity of 300ft/sec?

Big ports can still be fast on the bench. Sized for the engine they are going on for good velocity on the running engine at the rpm range used is what matters.

Rick

I would agree, but with a project such as this it is impossible to nail down all the specifics. If at the end of the head job they do not match the multiple cubic inch shortblocks the party is thinking of they will go on the next project!
I am only able to measure velocity at this point on the bench. After looking at the numbers I am hoping to get my 310 cfm at .7 lift with near 300ft/sec if I can avoid making them sprinklers! Thanks, Charlie

[Abbottracingheads]

Those heads will go over 300 no problem, but you are going to have to port them. From the pictures I can tell you are just starting to port them. You have not done much more than clean the casting. Big air does not move through tiny holes. Motors do not make big power with tiny ports. Tiny ports belong on tiny motors. Big ports have plenty of airspeed when done right. Keep at it. The internet has a lot of misinformation on it. I have have been doing this for 40 plus years and am still learning. Stay after it.

[Carnut1]

1226161214_HDR.jpg

Little more work after airspeed check. Last flow with 1204 gasket size. Chamber brought out to 400 head gasket on intake side. Old exhaust flows on graph. Thanks, Charlie

[Carnut1]

1226161221_HDR.jpg

Last 1204 pull graph.

[randy331]

From the pictures I can tell you are just starting to port them.

He said a 200cc head that is now 224cc, I consider that more than just cleaning the castings.

Randy

[Carnut1]

1226161226_HDR.jpg

ft/sec graph unported vs. Ported.

[Carnut1]

Those heads will go over 300 no problem, but you are going to have to port them. From the pictures I can tell you are just starting to port them. You have not done much more than clean the casting. Big air does not move through tiny holes. Motors do not make big power with tiny ports. Tiny ports belong on tiny motors. Big ports have plenty of airspeed when done right. Keep at it. The internet has a lot of misinformation on it. I have have been doing this for 40 plus years and am still learning. Stay after it.

I love posts like this! I am only 35 years into cylinder heads but I am not a pro. Most of my junk was iron street stuff. I am sure these will be over 230cc after cutting for 1206 gasket and raising the roof a bit. Thanks, Charlie

[Carnut1]

I figured I should check. 228cc cleaned up port 1204 gasket. Thanks, Charlie