52 twin H issues.
This car has sat fo some years with lite use for the last 20. Car has 42k on odo original paint interior etc. twin h manifold was ate up so found a decent replacement. Rebuilt cabs extremely throughly, ignition and fuel system ( tank pump lines). Put a block off plate between intake and exhaust manifold due to suspect Welch plugs at bottom of intake. Car ran awesome! Carbs synced up nicely etc. the car sat for couple months then went to our paint guy to do his best to bring back the original paint. Then sat for another month or so. Now we have a horrible idle, very rough. Pulled carbs down they are good and synced as close to perfect as we can get. High end runs great. Compression is close to 100 on all cylinders except the two center cylinders (3&6). Going to pull the head I guess. Just have a hard time believing after running so well from its long hibernation this starts out of no where. Any dumb ideas I’m not seeing?!?!?