Great car Rolf, and welcome to the forum. I also fitted Webers to mine but transferred back to the original 4bbl. Did you re-locate your alternator down low at the front? For your information it is possible to run a jackshaft (but not the original) so you can have alternator and A/C compressor as in a standard car if that's what you wanted. You have to fabricate but quite a simple process if you want details.
And if you were offered the build sheet from "Mr Vito" for €750 you're lucky, he quoted me €3,000 a long while back!!! But not sure he's had many takers. I too was told of certain "special features" for my car that Lee mentions. I didn't proceed.
Good luck with your car, it's beautiful.
Best
Larry (8MA 1028) in UK.