The Darracq V8 - Carburation

V8 carburettor detail Darracq carburettors V8 carburettor detail
V8 carburettor throttle detail Looking from the engine manifold, half throttle
V8 carburettor splatter plate Splatter plate to help vapourise the fuel, since the air flow is concentric with the main jet not perpendicular with it
looking deeper past the splatter tube, the casting is threaded to take a venturi insert, we think
anybody any ideas for main jet size or venturi restriction ratio?
V8 carburettor venturi missing
Zenith of period Zenith carburettor from period with many similar design features On right, same diagram but colour coded by me
Blue is main fuel feed to main jet
Mauve is auxiliary for medium speed running
Green is slow speed running
Yellow is venturi
Zenith  now colour coded