[66GT305PS]

With all that extra volume being pushed in you need good out-flow. Without good headers and exhaust, you will not get the full effect. My 66 GT350 with a Paxton runs well. I would be sure that you have a good ignition as well, Petronics at the minimum, multispark is better.
If you are good at mechanical work and tuning the carb and timing, it should take you a weekend. Setting the carb (600 is perfect for your set up) with proper jetting is critical and may take a few runs. Check with Paxton as to the recommended setting with your cam, rollers, etc.

You will love the result. Feels like you dropped in a Cobra Jet.

[snaranjo]

I have a decent bottom end - forged pistons, but cast crank with Dart aluminum heads, and Hedman shorties and Flowmaster exhaust. Go enough flow I think. But, I'm a little concerned about my compression. I am running about 9.7:1 which I've heard is too high for a super-charger even with a low amount of boost. What is your take on compression?

[66GT305PS]

A supercharger will raise the compression value about 2 points. I lowered the K code engine to 9:1 because I wanted to be able to run pump hi octane gas (91) on standard timing. For general cruising you should be okay, but check with Paxton. If you are going to be using the car for any type of hard racing, drag or road type, you may need to lower it or add higher octane fuel.

I expect you are putting in the newer unit from Paxton/Vortec, not the original 1960s vintage set up (that I have) available from Paradise Wheels.

The overall set up is perfect and just waiting for that hair dryer to be installed.