There is nothing inherently wrong with the 307. It just doesn't have a performance reputation as Chevy didn't try to enhance it with choice performance parts, so there is no mystique surrounding it. The 302 Z28 (4" bore 3" stroke) took care of that. The common 350 has more torque without even trying, by virtue of it's displacement.
The 307 actually has decent nickel content in the block, has a better bore / stroke ratio (3.875" bore 3.25" stroke) that the common 305 ( 3.736" bore 3.48" stroke). The small bore makes piston manufacture more of a specialty item than a mass production item, so the 307 is less desirable by virtue of the higher piston cost & lower torque compared to the 350. The 307 will always seem to be less than when compared to the 350, but the 307 did what it was designed to do and was a decent engine.
The 307 actually has decent nickel content in the block, has a better bore / stroke ratio (3.875" bore 3.25" stroke) that the common 305 ( 3.736" bore 3.48" stroke). The small bore makes piston manufacture more of a specialty item than a mass production item, so the 307 is less desirable by virtue of the higher piston cost & lower torque compared to the 350. The 307 will always seem to be less than when compared to the 350, but the 307 did what it was designed to do and was a decent engine.
