Questions Related Spider Restoration

I am restoring a 1980 2000 Spider and have some questions I hope someone can help me with. I would like to replace an old Weber 28/32ADHA7/180 with a new Weber 32ADH using the original intake manifold, "S91" 132AC2C000040/9 (don't know what is necessary to ID the manifold). Is this replacement possible and if so, are there any necessary modifications I need to be aware of for this conversion? I could also replace the maniflod with a 132AC.1C0000.40/5 - no exhaust recirculation - but that may be beyond my capabilities at this point. May consider later. Any comments?
Also, the shop manual calls for check valves in both fuel lines from the gas tank. Are these really necessary to stop back flow? If so, where can I get the check valves? I have not had any success in finding a source. Any help would be appreciated, this is my first restoration and my first Fiat.

Larry Muschiatti

Sorry I can't help but welcome to the Forum.

I'm sure there's at least one other Spider owner here somewhere (also in the USA) but I haven't been able to find him yet. Lack of time, sorry!

STEVE - the NOS guzzling Panda owner and beagle fanatic ...