Rebuilt top end of engine now carb idles much higher?Please help

Where is your initial timing set? In other words, where is the timing at "idle"? If it's at 36* at idle, there's your problem. It should be "somewhere" between 12-20* at idle and I would go no more than 34* total all in by 2500 on a big block. Disconnect the throttle cable and start it up. See if the throttle cable might be holding the throttle open some.