The header was full of dirt and cleaned in  August 2009; the four holes for the 4 barrels of the old Carter 3131/3249 are all the same diameter. This does not allow to fit a modern Edelbrock 1403 as its secondary throttle valves are bigger than the holes in the header. Solution: entrusting Officina Bugamelli with the task of enlarging the two rear holes to fit the Edelbrock's throttle valves

The first step is to widen the holes on the header

It is a precision job, and the intake tracts were polished with care to improve the flow of the fuel/air mixture

The finished thing looks great and now the throttle valves openings match perfectly the headers holes. Please also note the polished brass joints

A perfect match

Now it is possible to remove the plastic 1" spacer that had been fitted to allow to the secondary throttle valves to open. The original Bristol air cleaner box has replaced the chrome Edelbrock cleaner that was a bit garish for my tastes (on a Bristol at least)

A much better-looking engine bay, very similar to the original but with a new carburettor, alternator, coil, radiator, etc