The Weber carburetor only helps if you rev the engine up. Below 4000 RPM it won't make any difference.

The key is to rev up the engine. That's why a 5-speed won't give you quicker acceleration, nor will it give a higher top speed. It only reduces the revs for quieter more fuel efficient highway driving

Yes, an electronic distributor is an "electronic ignition system". All California B310 had them starting in 1975. They don't make more HP, but they keep the spark in perfect spec year after year (with a points-type ignition you have to check and/or adjust the dwell every 3 months)

"small cam & lifters" -- The stock cam makes maximum power at 6000 RPM, so if you want to make maximum power at a lower RPM obtain an "RV" cam as they call them here in USA. Any time you change the cam, new lifters (or refaced lifters) are required

"set of extractors" means an exhaust header. See our Headers tech article. It won't make your car accelerate faster, but it will sound faster