Thread: 70 chevy with 350 engine trouble

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Just thinking out loud here, but since you've shown that you had a weak spark I'd say chances are pretty good that you're dealing with an ignition problem. Unless you changed out something in your fuel supply system, like if you added an electric fuel pump that you have not mentioned, I would think that your operating fuel pressure is probably OK and you're not pushing fuel past the needle valve to flood the float bowls. Now it's entirely possible that your needle & seat have aged and might be leaking, but the fact that you changed the coil and got an hour of good running before it started going funky makes me question your ignition system. Charlie mentioned the possibility that you've fouled those plugs, and another question is what brand plugs did you buy? There have been too many cases where new out of the box plugs are bad since the manufacturing shifted to China, and it seems that AC plugs have been hit hard.