Weslake's Experimental Dualflow 100S Head

Weslake's were experimenting on DHMCo's behalf with a type of 100S head that was not in fact crossflow, but more correctly dualflow. To be specific, as well as having the intake and exhaust manifolding in its usual place, the off side carried two smaller inlets, where two additional carburettors were positioned, ie running with four carburettors. Weslakes idea, stemmed from similar work that they had done on MG's, with a view to having a greater volume of gas in the larger chamber behind the valves. Yes, it did produce more power, unfortunately only if you manipulated the throttles independantly through the range. A minor problem, not able to be solved prior to a time when they lacked Pentium 3 computers and regularly putting men on Mars! In the end, Weslakes came up with the idea to put an equalising pipe across the two inlets on the offside and with that gave up on the rather expensive project.
To my knowledge a couple of dualflow heads existed, I managed to buy just one of these heads, including the test data, from Weslakes, as it was still laying under the bench twenty years after testing ceased. Incidentally, you can pick Weslakes test heads, they will be stamped on the rear vertical face of the head RA249, or whatever the test number will be. Ten RA stands for Rye (the town on the English South coast, East of Brighton where Weslakes are located), and the A stands for, yep, you guessed it Austin!
(Oh, I might mention before anyone rushes to the phone, I picked that place cleaner than the turkeys breastbone on Thanksgiving day!) Despite the known problems, a friend subsequently fitted it to AHS 3909 in four carburretor form. Impressive under the bonnet it was, the eventual resulting reasonably spectacular fire, was not! With the 100S surviving, the dualflow head was again reduced to the role of a interesting doorstop.

The Information above is an excerpt from a message posted to the S.O.L. Healey Mailing List by Joe Jarick
Thanks to Steve Pike for access to the Head