Single-plane manifolds are used with camshaft, valve, and cylinder head modifications, to let the engine breathe better at high RPM's. If you're going to turn it up above 3,000 RPM a lot, and you're willing to invest about $1,000.00 in trick stuff to make it work at that speed, that manifold is just the thing! The 307 engine is getting very popular with some guys who run special classes at the drag strip, something about having the right weight per cubic inch to stretch the rules a little. It was a pretty lousy combination back when the 327's and 350's were the high HP options. The 307 sort of replaced the 283 as the economy V-8.
The engine will run OK, not great, with the single plane manifold, and that 600 CFM carb will be about right for your application, but you can expect some low-to-midrange sluggishness with the single plane manifold. Once it's wound up, the power increase should be pretty noticeable. It looks cool, though, especially with a big chrome air cleaner!
Jerry
