I went through this decision and back and forth between using 2v and 4v heads over the past 20+ years of running Clevelands. I have run both, and now run a set of the Aussie heads. The 4V heads can be run on the street and not be too much a headache if the engine is built right, they have better compression and allow more performance options, especially when taking more advantage of the mid to upper RPM range. If you are running stock gears I am afraid the 4V heads may be a disappointment since getting the revs up faster will be where these heads shine the best.
The 2v heads are no slouch and will give good torque from idle and through mid range and will work better with stock gearing. The are lower compression but can have detonation issues due to the open chamber design, especially with the wrong cam setup.
The Aussie heads are a mix of the two and some believe the best of both worlds, especially if you work the heads a little. I think they are a great cast iron head for hot street performance, they are absolutely wonderful with my current setup. They have also been fitted with the larger 4V valves (2.19") but be VERY careful if doing this, if not done right you can hurt port flow if the ports are not blended properly into the valve area. I spent many hours working on this and CCing the heads.
The 2v heads have good ports for the street if you want low-end torque performance, but I just don't like the large open chambers as they don't promote efficient ignition in the combustion chamber.
But like said above, run what you have, putting a 4bl carb and maybe some headers will do alot for the 2v cleveland.
Also, I would recommend the Edlebrock Performer RPM Air-gap intake as mentioned above. It does sit a good bit higher and may cause clearance issues with your hood, so be sure to check that out first if you go that route.