[Spridgets] head question

[David Lieb]

>>> What is the advantage of a crossflow head over a stock type flowed head?

>> I assume a crossflow has the intake on one side and exhaust on the other.

> True, With no shared port like the A-Series head.

The "siamesed" intakes on the A-Series and B-Series heads are a major
impediment to performance. If you look at the firing order, you will
see that the engine is inhaling through the front intake for two
cylinders, then through the rear intake for two cylinders. This means
that the flow is constantly interrupted and keeps accelerating and
decelerating. I believe this is one of the reasons that the single
1.75" carb tends to out-perform the twin 1.25" carbs. I know this is
one of the major reasons that it is so difficult to do a good job of
updating an A-Series to multiport fuel injection like MegaSquirt. It
is also one of the benefits of the 1500 Triumph engine...

One of the nice things about the Pierce crossflow head is that it
retains the three-exhaust port configuration of the standard A-Series
head so that readily-available exhaust headers will still work fine. I
don't really appreciate the fact that it incorporates Weber intakes,
since this would probably make it more difficult to fit throttle
bodies for fuel injection.
David L