[tubman]

I think "quickchange34" is referring to the advance curve build into the distributor while you are talking static advance, two different things. Most new flathead distributor these days come with a SBC advance curve (34 degrees when a flathead only wants 22) which will give way too much total advance at speed. The only solution to get it to run right at cruise is to retard the initial static timing which causes the overheating. It is the advance curve (weights and springs) that need changing.