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Message: <blockquote data-quote="Kilgon" data-source="post: 352932" data-attributes="member: 5840">I'll try to help a little.1st -  The carb should not bleed off like that.  Only a few ways that I know of for it to be losing fuel out of the bowls.  Bad seal or crack in bowl or metering block. Your float could be set too low and you don't have enough to last overnight.  Right after you shut the engine off do you see fuel in the sight glass - if not then you need to adjust your floats again.  Leaking through the power valve.  Weak fuel pump that is not providing enough pressure to keep the bowls fill.  Green on the brass float would almost indicate a reaction to one of the additives you put in or water in the fuel.2 - Carbon fool plugs are a sign of running rich which is caused by the carb out of adjustment, oversize power valve, weak spark or not enough air.First try to adjust the carb following Holley's instructions for your model.   Seeing that you had a larger cam put in the engine there is a good possibility that you need to go to a lower power valve.  This is something that is overlooked way to often. To check the size you need you will need to see how much vacuum you are pulling at the manifold.   Using a vacuum gauge see how many inches you are pulling at idle. Take that number and divide by two. ( Ex  10 in vacuum / 2 = 5). That is the power valve size you would need.  Odds are you have the stock one that came in the carb from the factory which is a 65.   Having the wrong power valve can cause it to be open at idle causing a rich mixture.Weak spark is usually a coil issue.  Sounds like you have already address those issues on the electrical side.  You may have the wrong heat range spark plug causing some of your problems also.  Need to check.  Look on line for spark plug color diagnosis and also a heat range chart.   To get a proper reading you are suppose to put in new plugs, drive 35mph and turn the engine off.  I just put in new plugs and drive around the block and shut it down right before my house and coast into my drive.  Be careful not to lock the steering.3. Sputtering and dieseling.  Timing, air fuel mixture or foul plugs once again.  The normal timing for a stock 351 is 6 to 12 btdc with a total vacuum of 36*   If the timing was at 22 at idle then added the vacuum advance you could have gone over 40* or more and have caused some engine damage.  Try setting the timing at idle with the vacuum line disconnected and plugged to around 10* and see how the engine runs..  If ok then hook up the vacuum line and run the rpms up and see how it runs.  Take a quick run around the block.  See if worse or better.   Either way this will give you a starting point to adjust your timing from.   Try to find the optimal setting by adjusting just 1 or 2 * at a time.Also wouldn't hurt to try and get a fresh tank of gas.If all of the above fail then you may have to start tearing into the engine.I would address one area at a time and not move on until I know I have eliminate all the possibilities in that area.    Make notes of what you are doing and how it reacts.Hope this helps a little.</blockquote>

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