Stock Cleveland 351 2BBL 3-speed manual convert to 4BBL, manual or vacuum secondary?

[IstoT]

Howdy. I'm not good at car mechanics and I've just started this hobby in my old days so I'd like to have other opinion before I made last decision.
I thought all over again and decide to forget my two step upgrade and buy both carburetor and intake manifold in same time.

My car is purpose to be almost original and mainly for street use. I'm thinking to go manual secondary because I have 3-speed manual.
After long thinking my two carburetor choices are Holley Brawler 600 CFM or QFT HR-Series 600 CFM. Are these good choices, and which one you would prefer than the other and why.
Or would it be better to stay at vacuum secondary carburetor (both model have that too). Best regards, Isto

[Gaz64]

600 vacuum secondary on 3 speed manual. Depends on the engine as to how much carb you need. Gary