Dart Cylinder Heads for Ford

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Flow Testing
We hauled the heads over to Rob's Auto Machine so Rob Jr. could flow test them on their Supeflow SF-600 flow bench. As usual we're testing at standard 28" pressure and using a 4" bore. A radiused fixture is used on the inlet. We didn't use a pipe on the exhaust to simulate a header primary, which would have slightly increased the exhaust flow numbers we obtained.

The initial flow numbers showed the 210cc intake to flow exceptionally well from low lifts all the way to .600" where we stopped taking readings. At .300" valve lift we measured a gusty 195cfm. For comparisons sake, the low and mid-lift numbers outflow heads like the Trick Flow Twisted Wedge, indicating this head isn't sacrificing bottom end for high lift gains. At .600" we measured 285 cfm.

The exhaust side also shows stellar flow characteristics. In fact, the exhaust number are better than the intake numbers on certain aftermarket heads, driving home our point that you must have sufficient heads on a big-inch small block Ford. At all points the ratio of exhaust-to-intake flow is 77-79%. This ratio is important to look at especially when considering cylinder heads for a blown or nitrous engine where evacuating the large volume of spent gasses is paramount for making power.

Dart Pro-1 CNC 210cc Flow Data
Flowed by Rob's Auto Machine, Hayward, CA. (510) 732-1909

Our cylinder head gurus poked and prodded the runners and bowls and determined that they may be able to pick up some flow by smoothing out a tiny groove that is a result of the CNC process. The CNC tool can only port so far into the bowl, then it needs to come in through the port side. As a result a small groove is left in the short-side radius, the hardest to access area, in both the exhaust and intake runners. The groove would likely cause air-flow in the critical short turn area to become turbulent. We carefully smoothed this out and re-flowed the head. The results were well worth the efforts, with as much as 15 cfm a .300" lift. We don't recommend that you put a grinder to your heads unless you are experienced in porting and understand that just as easily as we improved flow, it's much easier to disrupt it and hurt flow tremendously.

Looking Forward
With a near 300cfm head we're just as nervous as we are excited about the idea of upgrading our Vortech-blown 331 project. This sort of flow will surely bust the already stressed stock 5.0L roller block. Of course in our demented power-hungry minds we are secretly looking forward to splitting the motor -almost as if it were some sort of rite of passage before being allowed to make really big horsepower!

Sources:

Dart Machinery
353 Oliver Street
Troy, MI 48084
248-362-1188
dartheads.com

Ford Powertrain Applications
7702 E. 96th St
Puyallup, WA 98371
fordpowertrain.com

Rob's Auto Machine
27515 Industrial Blvd.
Hayward, CA 94545
Phone (510) 732-1909
robsautomachine.com

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	FM Tech Editor and cylinder head aficionado Jim Langley and head porter Rob Stuchlik Jr. of Robs' Auto Machine analyze the Dart 210cc head.

	Dart's incredibly precise CNC machining process is especially evident when looking at the shapes and transition around the guide boss area. As with any machining process the cutting head can only reach so far into the bowl before having to come in from the port side. As a result a slight trough left behind at the cutting junction on the short side radius. We found some additional flow by smoothing this out.

	Convinced he can gain some flow, Rob performs a quick smoothing of the above-mentioned CNC groove. This sort of "tampering" isn't recommended unless you really understand what you are doing, as it doesn't take more than a few rotations of a grinder to hurt flow.

	While not equipped with a wet-flow bench, the dry Superflow bench at Rob's gave plenty of evidence that the Dart 210's are an ideal head for our stroked and blown project.