HEI Question - Troubleshooting

Hi everyone,
I am the guy who had posted a request for help with a carb fire that turned out to be caused by the distributor rotor coming off. After replacing the rotor, I noticed that I had poor performance and a lack of power. I noticed that the dist. cap didn't look too good after the rotor came off, so I replaced the cap to no avail. I then rebuilt the carb incase something had happened when it caught fire, but that didn't seem to help either.

I decided to see if I might have a problem with a particular cylinder not firing or something, so I put a tach on the dist. and started her up and watched as I removed each spark plug wire one-by-one to see if any of them were not providing power. I found that removing the plug wire from cylinders 8, 3, 5, or 2 did not cause a reduction in RPM, and actually caused it to increase a bit. There is a spark occuring on these cylinders, but they are not adding any power to the engine. The fact that these cylinders are every other one in the firing order, coupled with the fact that I had a rotor failure, has me convinced that something must be wrong with the ignition system.

Does anyone have any ideas as to what could cause the engine to only run on every other cylinder? Please advise. I would like to avoid replacing the entire distributor if I only need to replace the coil or the module, but I'm hoping that there is enough information here that can point me in the right direction.

Thanks.