I have a 1965 Catalina Ventura 389, and i just started it up for the first time after the snow came.  at the end of last summer i had a cam, lifters, pushrods etc. put in, and i threw on an edlebrock 650cfm carb.  other then that, its all stock.  When it fired up, it idled at about 1500 (i dont have a tach) and would idle for about 15 seconds at the most then it dies... i can keep pumping the pedal and it will stay running, but it goes back to idling way too high for a couple seconds before trying to die again.  And one time, i swear it was idleing at 50 rpm hahaha i could  hear one cylinder going threw a stroke about every one second haha and it did that for like 10 seconds....im confused, please help me  

Sounds like you might have a bad vacuum leak. When you pump the gas, you compensate for the excess air and it revs up until the fuel leans out again.  What intake manifold did you use? If it was a dual plane like the Performer or Performer RPM or a 67 and up stock manifold, you may have a problem with the carb not matching the intake. Check to see if there is any place where the square bore carb comes really close to the edge of the spread-bore manifold opening, even if it has 1/16" of overlap, often the engine will suck air thru the gasket because there isn't enough clamping surface to hold it tight. You may have to get a thin carb spacer plate and sandwich it between two gaskets. You can check for a vacuum leak by running the engine and spraying carb or brake cleaner in small bursts around the base of the carb and listening for the rpm to pickup, of course if it's so bad that it won't stay running you need to pull the carb and check that gasket crush first. Hope this helps.
Steve