[Russ/40]

Adding to what has already been said, I'll bet you have a poor wiring job. Did you put the 8 volt battery in? Usually they end up in cars as people try to cover an electrical problem. I suspect there were problems that ended up with the 8volt. Check the overall health of your wiring. That means good clean and tight connections. I disagree that 2 gauge is appropriate for battery cables, use 0 or 1 gauge. Does your car have the appropriate gauge wiring harness? Is your starter in top shape with a good bare metal ground? Starters pulling too much current will draw the ignition voltage down to levels that may be inadequate for the proper spark.