The '66-up SBC engines that came w/a 4-bbl carb almost exclusively used the Rochester Quadrajet. I will always recommend one of these for any street driven engine that isn't running a big cam or is strictly race orientated. Use an intake made to accept a spread bore carb, using an adapter to fit a spreadbore carb on a squarebore intake is a bad plan- too much restriction from the adapter.
Next to the Q-jet, either a Holley like the venerable p/n 1850, model 4160, 600 cfm w/vacuum secondaries or an Edelbrock p/n 1405 or 1406 600 cfm or the Thunder AVS series p/n 1805 or 1806 650 cfm carb. All these carbs except the Q-jet are squarebore carbs. Some intakes are designed to take either type carb, just be sure before you buy that the carb and intake match.
If you have emissions inspection these recommendations might not fit the need.