Hi Nick and Barrie,
Please find some pictures of my carburettors enclosed. Externally they do look identical to any other H2 carburettor that has dampers. Interestingly enough I just spoke to a friend that has an early Aceca, I.e. from the spring of 1955, and that car doesn’t have any dampers either.
I realise is that I might be totally wrong since I assumed that later cars have dampers. This is an assumption based on the fact that I have bought a number of carburettors that were supposed to be from later Ace’s, and they all have dampers…
To try to answer your question Barrie, I did read on an MG forum that MG changed to H2 carburettors on the TC’s, with dampers in August 1947. The reason was that during hard acceleration the (xpag) engines sucked too much air resulting in a too weak mixture. I’m obviously no expert and I have no other evidence for this.
Obviously the Weller engine is also a different beast compared to the MG TC engine.
I also believe the question has to be changed a bit, did any later AC’s with the Weller engine have SU carbs with dampers?’
Jonas
Note, the top image shows the solid piston.