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john charlton · 08-04-2017, 08:59 AM

Ford built AA Trucks in England into 1936 . These were factory fitted with model B engines and carbs . At first the A inlet manifold was retained as the RHD manifold has a peg on it for the advance/ retard linkage pivot . These inlet manifolds were not bored out to suit the larger bore B carb so there was a 1/16" step in the inlet tract which Ford seemed quite happy about . Later production the advance/retard lever was deleted on the steering column and the B distributor fitted . I think that it would only make a difference at very wide throttle openings as the throttle plate is a much bigger obstruction to flow than the manifold/carb mismatch .I have a car with a B carb on an A manifold and it runs like a champ . Just wondered what a dyno test would show at normal throttle openings I cant think there would be much difference IMHO !!! I do have an English B carb (different markings on it) I ought to check to see if the mounting flange is aligned for the GAV driver .

John in sunny Suffolk County England .

08-04-2017, 08:59 AM	#31
john charlton Senior Member Join Date: May 2010 Posts: 1,304	Re: Model B carb on a Model A Ford built AA Trucks in England into 1936 . These were factory fitted with model B engines and carbs . At first the A inlet manifold was retained as the RHD manifold has a peg on it for the advance/ retard linkage pivot . These inlet manifolds were not bored out to suit the larger bore B carb so there was a 1/16" step in the inlet tract which Ford seemed quite happy about . Later production the advance/retard lever was deleted on the steering column and the B distributor fitted . I think that it would only make a difference at very wide throttle openings as the throttle plate is a much bigger obstruction to flow than the manifold/carb mismatch .I have a car with a B carb on an A manifold and it runs like a champ . Just wondered what a dyno test would show at normal throttle openings I cant think there would be much difference IMHO !!! I do have an English B carb (different markings on it) I ought to check to see if the mounting flange is aligned for the GAV driver . John in sunny Suffolk County England .