Okay, basically the little details...

New Gasket Set on my 350 nothing leaks!
Brand New Holly 600 Carb! - Old carb made it run like crap all the time.
FPR is sitting on 6 PSI I've attempt to increase it to see if it help'd and it didn't so back to 6 PSI.

Now when I start the car it fires right up "cold" great or "Warm" great...
When I go to rev it up in park it purrs nicely and sounds really good.

When I go and put my car in Drive it'll bog down and sometimes die, when I go to drive it, it won't gittie up and go at all it is slower then a Geo...

I read it could be plugs, wires, button, cap and stuff like that but just wanting to get some more info before I go and replace a few more things...

Anyone able to generate what is most likely the issue.

Plugs?
Wires?
Button?
Cap?
Timing? - I think timing is good it fires right up cold.
Fuel Pressure? - I think this is right at 6 PSI
Vacuum Leak? - Unless it's a vacuum leak not in the carb doubt it's this the carb is brand new.

Anything else to suggest? The Dizzy is out of a speed boat so it fires backwards and like I said it runs great in Park.. Lol just not moving!

 

Check your timing First! Just because it runs doesn't mean it's correct. Timing should be set at 6* to 8* without the vacuum advanced hooked up and the vacuum port plugged.

When you installed the new carb did you do the following things:

Adjusted the floats to the proper position
Adjust the idle mixture screws
Adjust the idle speed
Adjust the accelerator pump lever. This must be done with the throttle at full open and then manually depress the lever. The gap between the lever and the adjusting bolt should be between 0.015"-0.020"

Here's a good reference for setting up your Holley

http://www.holley.com/TechService/Library.asp

 

You can also check fuel pressure while driving. Tee-in a gauge with a hose long enough so you can see it while driving.

 

Sounds like a timing issue (or fuel volume). What distributer? What are base and total timing? Any vacuum advance?