Hi all I have a 65 Wildcat with a 425 dual quad. The intake is an Offenhauser and the carburetors are Edelbrock 600cfm's. The distributor is an MSD with a MSD Blaster Coil. When I fire it up, it has some trouble keeping from stalling, but after a 30 second warmup, it runs smooth in idle. Then I can drive around for about 15min, where the engine is running perfect. Then it suddenly starts sputtering or jerking. At any constant speed and light throttle. When I give it full throttle, there is no problem. The electric choke is working as it should. Plugs are new. Distributor cap and rotor are new. Could it be a faulty coil? Intake manifold gaskets?