Slightly late ignition timing will also increase exhaust temperature pretty dramatically. I've seen cast iron exhaust manifolds get red hot from late timing, and those headers are going to be close to cherry red on a long uphill pull, even with normal timing. On the dyno runs we did we would have to swap the headers side to side and turn them upside down, facing the collectors forward to keep the heat away from the dyno operator. I could actually see the flames dancing around inside the header tubes when we got above 500 HP on some of the circle track engines we built.
Jerry
