I recently rebuilt my 68 Olds w/400. I replace the distributor ignition with an HEI, the stock intake with and Edelbrock performer 455 and the Q-jet with an Edelbrock 600 carb. I'm experiencing a surge in the engine at low RPM's. It almost feels like a miss, but goes away at higher RPM's. I've put new plug wires,plugs,fuel pump and filter, and even run a wire direct from the battery to the Distributor ( I thought maybe low voltage somehow). The HEI distrubotor is new, but it is an in-expensive aftermarket one. Could an ignition module cause the surge, or do they just fail altogether. Any suggestions will be greatly appreciated.

 

You can generally remove the HEI module and have them checked at your local auto parts store. They aren't very expensive if they are bad.

 

"Surge" and "miss" are two different symptoms, with two different causes. You'll need to clarify.

Define "lower" and "higher" RPM.

Whether it's a "surge" or a "miss" it's highly unlikely.

Norm