57 AENDL new coil, points and condenser. Check ed timing TDC and x Mark spot on. Great spark hard to start. Will backfire through carb. Tried multiple carb adj. Will only start (when it starts)only run for a few seconds. Like its fuel starved. Pull plug it's slightly damp. Compression 80psi and I put air in the cylinder at DTC no leaks in intake or exhaust. There plenty of gas in the carb the air cleaner housing leaking a little and it's premium. Could an intake valve be sticking on this? Driving me nuts! Any ideas? Thanks.