Charging system and other wiring change help needed

I started the car tonight! Wow, what a great feeling. At this point the wiring seems to be ok. I didnt run the car for more then about 2 minutes at a time. I was keeping my attention to the wiring and making sure nothing got hot and all seems ok there. I didnt get a chance to check and see if I had enough output from the alternator but I will check that tomorrow night. The only problem I had was that when it first started it had a very bad popping back thru carb. I checked all plug wires and found all good there. I then went to the connection where the distributor plugged into the leads for the ignition box. The 2 wires coming out of the distributor were not indexed into a plastic connector so I didnt know which way to hook them up. I switched them around and everything cleared right up. Now I can put them into the plastic connector for a permanent connection.
I do have a question about the ignition box wiring. With the 2 leads that go to the distributor from the box (orange and black) they are a little short making the connection from the distributor to the box very tight. These wire do not use a copper type strand but they are a silver color strand. Is it ok to cut them and extend them with the standard type wire.
Thanks Rod