[Gordon Levy]

In todays terms that is a really small cam. Make sure you use a roller, flat tappets cams are to problematic with the changes in the hardening process in recent years. Also if you go to a 58CC chamber you will have around 11-1 compression. That would be marginal at best with todays pump fuel.
I can't say I am a fan of any of the heads you listed for various but it is your engine. I do understand wanting the weber look, I would use a stack EFI system as weber do a lot more work and far less reliable.
These are purely opinions based on what I have experienced over the years.

 

[Gordon Levy]

I am a dealer for Inglese and FAST and have used the EZ system a few times. It does work quite sell. You want to put the O2 bungs in the sidepipe collector and not on single tubes.
Most of the cams I use on small strokers are in the 500 range on lift and I find a 200CC head works best for the 331-347. If you want to turn the engine 7000-8000 revs you really need a solid roller.

 

[Gordon Levy]

You can do a solid flat tappet cam but a solid roller would be a better choice. This is mostly do to the hardening processes with flat tappet cams. The EPA has changed the allowed process for hardening and the quality just isn't there any more. You run a real risk of flattening a lobe unless you put in break in springs and them break in the cam properly them change out the springs to the correct tension springs for the cam. It's just a ton of extra work. We can also do things with a roller profile that you can't with a flat tappet.