What is the correct inlet manifold ?

[DerekAJS30]

My Model 30 has the wrong inlet manifold - Carb is 1 1/16 while the manifold is 1". Threads are chewed up too.
Looking at the parts catalogue, model 30 should have part number 023406. However looking around on the net for a second hand one, nothing comes up, only 011633 (model 20) and 025091. Some are advertised as 1" and some 1 1/16". Plus some have a rubber ring seal and others do not. My carb already has a rubber seal so flat would be best. It seems then there are variants of the same number manifold which is rather confusing.

Can someone please untangle this for me - what do i need ?

Thanks, Derek

[dave16mct]

You need 023406 with 1 1/16" intake hole. The ones with the O ring are pre-'55 G9.
Dave

[Duncan]

If I recall correctly, Steven S advised me quite a while ago that although the M30 carb went from 1956 @ 1" to 1957/58 @ 1 1/6 and the manifold increased accordingly the cast part number did not change so best to get a measurements as the 011633 may not be 1". I may be recalling incorrectly however.