Hello, Since buying my Jeepster about 6 months ago I have read alot of posts on this site but have not had a reason to post my own question until today. My Jeepster is '67 with a '71 225 in it. I recently replaced the stock intake manifold and carburetor with 4 barrel holley carb. and offy intake manifold. The engine runs rough when it warms up, the 2-4-6 cylinders are running weak (about 40 rpm drop when spark plug wire is pulled), and foul the plugs. The odd cylinders are strong (approx. 120 rpm drop). The #2 cylinder is the weakest with a 20 rpm drop when the plug wire is disconnected. RPM drop is the same across all cylinders when the engine is cold. Any help resolving this issue would be greatly appreciated.