A 307 is a 327 crank put into a 283 block. What you get is a poor bore-to-stroke ratio and relatively small displacement. You end up with the displacement of a smaller engine with the rev limits of a larger motor.
A better combination is the 283 crank in a 327 block. That combination gets you a 302, as found in 67-69 Camaros. There, you get the rev capabilites of the smaller motor with more displacement.
Long winded, eh?
gfy
PS- It's not a bad motor... it gets bashed because there are better SBC variants that offer more performance for less money.