Let me see... not sure what it is exactly. Im thinking its my carburetor. This is on the 461ci. I have a 750 edelbrock, nothing fancy. It was a return at my work someone had a dual carb setup, it was barely used. Its ran perfect since I built it 6 months ago. But now when I turn the car off it putters and toys with me and doesnt shut off for a few long seconds, then I get an airy exhaust poof sound and smell out of the carb, then it turns off... I played with the timing and the carb... not a noticeable difference yet... ... what do you guys think.

could be that the throttle blades are too far open or the timing is too advanced.
but it could also be an ignition switch going bad. my Monte did kind of the same thing- i'd shut it off and take the key out, but it would run for about 5 seconds after that. i put in a different switch in it that i had laying around, and it shuts off clean now.
maybe test it by "hot wiring" the coil to the battery and shut it off by taking that off and see if it shuts off clean.

Bad Gas, don't they mix water with it in California? :D

Bad gasoline could definitely have somethin to do with it. And with the situation here in the states currently, I wouldnt be surprised if the gas has gotten even crappier lately.

First off, what exactly did you do with the carb, and what is the timing set at?

Although Im leaning towards some bad fuel, some tuning may help it out enough that it can work with the bad gas(maybe).

Whats your engine combo(and drivetrain combo)? That will help give us an idea of what your timing curve should look like.

Anywho, start off with a trusty vacuum guage. Hook it up to a full manifold vacuum source, block the cars wheels up, put on the E brake, turn the idle mix screws all the way in, then back them out even at 2.5 turns(make sure they are all the same). Now, fire the car, put it in gear(this is why the wheels are blocked and the brake is on) and have a look at the vacuum guage. From here, start adjusting the idle mix screws inwards 1/4 turn at a time. Alternate between the screws(in other words, adjust one, than adjust the other). Make sure you adjust them evenly(at 1/4 turn at a time). Keep an eye on the vac guage. During this process, you are adjusting the screws to acheive the best vacuum. Once you get there, stop adjusting.

Next Id mess with timing some, but its hard to call where you should be going with that without knowing your vital specs.

Also, how hot does the engine typically run? Depending on the current temp, a cooler thermostat may benefit you without any adverse effects(for example, if your running around 180 now, you dont really want to go any cooler....but if you run around 215 or so, bringing it down 20 degrees wont hurt anything and could help with the dieseling you are experiencing).