Originally Posted by AintNoHo

Just so you're completely confused now, the problem is not timing or plugs, it's too rich. The unburned fuel from the cylinder is continuing to burn in the headers. That's why the heads are cool while the pipes are red hot. I've done it while trying to make an fmu work. In addition to red hot pipes, flames would shoot out the open exhaust on let-up from a full- throttle blast. If it was too lean, the pipes would be normal but the heads and pistons would overheat and ping. In any case, let us know what you find.