I'd be looking at a few things:
-those rubber O ring insulators. They are trouble. My O-rings upon close examination were cracked; they can slip out when being installed, getting equal tension top and bottom while mounted on the car is a royal pain. I went back to paper gasket. In the pics, one of yours appears to be skewed. Mine used a coiled spring washer under the nuts to allow adjusting the tension/gap. Another brand had some sort of rubber washers. You appear to have neither. Check out
https://www.google.ca/search?q=dcoe+soft+mounts&espv=2&biw=2133&bih=1096&tbm=isch&tbo=u&source=univ&sa=X&ei=it1kVO7kCIqRyQTHQQ&ved=0CDIQsAQ&dpr=0.9
and Pierce Manifolds if you want to keep those. Or get the solid ti style insulators.
-fuel pressure regulator. All I know is that mine runs like crap if I stray too far from 2.5. I used a fuel pressure gauge to fine tune the actual regulator, which wasn't accurate.
-float levels. Italian model uses different spec than later Spanish as I recall. In any event, read posts on how to measure and adjust. Somewhere there is a chart with float levels for different models
-timing. I spent a lot of time fooling with carbs until I took IE advice on setting full advance to 33 or so. Made a big difference.
Also, if memory serves, Italian models take one turn out to start, Spanish 2.5. In any event, different base points. Try starting at one turn out..