DBB - DCO3 Weber carb inlet manifolds - externally an exact replica of the original DBB alloy manifold & linkage that uses DCO 3 carbs (these can be supplied aswell), at 65mm long they are a little short of ideal but AM fitted 6 ? MkIII's with them, These can also be fitted to the DB2 to MkII.

or

DBB - DCOE - manifolds to suit 40DCOE, we have a manifold that was made by the Service Dept  in 1954 and tried on at least one DB2/4 MkI (documented) before it was taken off (actually for Solex 40's but they have the same mounting flange as a 40DCOE), it looks very similar to the original DBB manifold but were in steel, we would make them in steel (still looks good) or alloy (very expensive but looks great !). These can also be fitted to the DB2 to MkII

or

well not quite the same but they are very pretty, with 3 manifolds (1 per carb) instead of one manifold for all 3 carbs, takes modern 40 DCOE carbs as they have different centres to original DCO3 carbs.

All of these manifolds have better internal shape than O/E manifolds so give better performance.

Can be used on LHD MkIII's with some sort of airbox which the original DBB manifold cannot.

Please tell us whether Alperform alloy head & which type, what engine type & whether horizontal or 5° required.