I'm trying to replace my resitance wire (see pic) and I think I found the bulkhead (see pics). It doesn't appear that the wires can be removed easily, I pulled slightly on the bundle but it didn't seem to want to come loose. Do these wires come out as a unit or do they come out individually? The last thing I want to do is create new problems when trying to solve the current one. Thanks.

There is a bolt (3/8" head ?) in the center of the bulkhead connector that needs to be loosened if not removed (this bolt on my 73 and 74 Nova's have retainer clips on them to where the bolt does not come out of the one half of the connector). After loosening the bolt wiggle the whole bulkhead connector on that side and try and pull it towards the front end of the car. If it come apart you can see inside the connector how the pins are held into the plastic housing. If the plugs only come out part of the way, loosen the bolt some more and try unplugging the connector.
When you go to reassemble it, make sure the connector pins are lined up before tighteneing the center bolt. If one connector is not seated you can have problems later or could push either side of the connector out of the plastic housing plug.
Both plugs come out at the same time. Once they are off of the other half of the connector on the firewall you can see how the plug is actually two pieces. One half goes to the engine (alternator, starter, distributor) and the other is for the front end lighting.

This might help:

http://hometown.aol.com/krystaldesigns/pageA13.html

Jim

Thanks Jim, I did see that bolt in the center but wasn't sure what it was for so I left it alone. Thanks again.

No problem. That's what that bolt is for (to hold it together). Just take your time taking it apart and reassembling it.
I tried to make it easy years ago for my neighbor swapping motors from a 6 cylinder to a V8 and left the harness attached to the V8 motor going to that bulkhead connector and he got it all done and said it wouldn't crank. We took the connector apart and he had pushed out the purple starter solenoid wire out of the housing. In his case he got in a rush. It was very hard to see with all of that tar crap around it originally.
I would also look at the other connectors in the plug and maybe try and clean them so you don't have problems later down the road. A lot of them I've seen the main feed wire off of the battery going through the bulkhead connector get's discolored from the amperage and poor connection and could give you other problems later like dim headlights, slow turn signals, and so on.
Jim

My recollection is that you have to pull the bolt all the way out to seperate the engine and lighting harness connectors from each other.

The top wire in your picture is the wire of interest.

IIRC the engine side is the male terminals in the bulkhead connector. I would remove the engine harness from the car completely. This will make it much easier to see and work on. The engine side of the connector body has a type of glue on it to seal things. You can work this out around the wire using a knife and small screw driver. Then you should be able to squeeze the terminal inside the bulkhead connector to unlock it from the connector body.

Thanks for the tips, I may get a chance tomorrow and have another stab at it. But like I said I'd rather check with the experts and make sure I don't create additional problems for myself.