Personally I'd try the 3.07's. Allow me to explain my reasoning.
Your zz4 makes very good torque at a lower rpm than many other cammed up small blocks. Look at the cam specs. It is very short on duration but long on lift. Something like 208 and 212 @ .050 IIRC. This makes for a lower torque curve. Plus a 10 to 1 comp. ratio with aluminum heads makes for efficiency as well as power. However detonation could be an issue on a hot day or poor fuel. You may have to play with the timing to get it dialed in. Acceleration would definitely be better with either a 3.42 or 3.73. I presume the reason you went with an overdrive was to improve hwy MPG and get lower rpm. This combo should attain that. Board member gchemist runs the same combo and claims close to 20mpg hwy. Now if memory serves he is in the flat midwest but so is the willamette valley. I personally would try them first before spending lots o'cash on a new settup. Just one Average Joes 2cents.
