[Brian]

I've run that very same manifold now for probably the last 20 years on various engines. The porting is rather small, this isn't necessarily a bad thing; it keeps intake velocity up. Thing I like about it is the carbs are positioned real close to the engine....I know others say the addition of risers aids performance, honestly I've never tried.
As this intake is for 8BA series, the carb bases are machined at an inclined angle. I machined these off flat, then the fuel pump hit the rear carb, so I modified the base of the fuel pump mount to 'angle' the pump for clearance...Plug the oil fill and draft tube holes with freeze plugs, and it'll go onto any pre 48 engine....