My experience with the 1405/1406 Edelbrocks is that they are jetted pretty close right out of the box, but because 99% are sold with 350 V8s in mind, you may have to make some adjustments with the metering rods and/or step-up springs. Edelbrock's owners manual is very detailed about how to correct various lean or rich conditions. And their 800 tech line is very good to help in sorting out drivebility issues. Just make sure all possible sources of vacuum leaks are closed before you hit that starter for the first time - there's nothing scarier than a new motor that won't run below 3000 RPM!
