Can a 1200 round port weber sidedraft manifold be fitted to a later model A14 round port head (the one with 2 studs per set of ports, not the single stud between the ports) Can lugs be welded on? Can a single stud be threaded into the A14 head? Any advice welcomed.

It'd be possible, but when these can still be bought new, I'd wait for a second hand one for A14/A15.

You'd be modifying the bolt pattern. and round to oval ports?

You can get a whole A12 head for < $50 second hand.
I'd do that. That would be cheaper than the labour you propose to use what you have.

Unless you live in Siberia, there are better options.

Cheers,
Chris

Thanks, I've had my 'round port head' rebuilt, so I'll stick with it. All the manifolds that I have found have been the single stud type. All the 'multis' seem to be for oval port or for dual carbs. My original plan was to use a down draft, but it ended up too high for my Triumph's bonnet.