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
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
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.
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!
353 Oliver Street
Troy, MI 48084
Ford Powertrain Applications
7702 E. 96th St
Puyallup, WA 98371
Rob's Auto Machine
27515 Industrial Blvd.
Hayward, CA 94545
Phone (510) 732-1909