couple questions

1; &50 cfm, the mentioned carb for sale is a 3310. Good all around performer.
The Performer intake should be dumped to the nearest 318 or fishing hook/anchor. It is NOT for your engine. It is NOT up to the performance specs.

2; Was properly answered. No problem. What you see is not the exhaust cross over uncovered. It is of no concern.

3; That is what the catologs say to lash at. I would follow that.