I did a swap of a '70 350 into a '77 k5 and it runs. I am so happy, but confused also. First, I have a wire left over. It is about three feet long, red, thick (like the guage off of the alternator) and has an eyelet on each end. I can't find out where it goes. The truck runs and drives fine as far as I can see, but it puzzles me. Also, the engine surges at all speeds and I don't know what it might be. It is the same carb/ignition set up I had on my last engine and it worked fine then. Can anyone help me with the wire or surging problem.