My old school 340 upgrades and results.

yep, I think it looks like a stocker. However, the problem could very well be starting after the electrical tape that I see on the wires. Also, the fact that somebody was in there and stuck the curve, well, there is another opportunity. the allen bolt is a sure sign of some down home country tuning :) .I think your sniffing the right trail, but I would start from the tape (i'm saying your after market ignition system).