Dave, I've always believed that full throttle runs like that does an engine good.
p.s. Is that an old Tower starter on the bench?
Barry look at the old bench run photo's and you will see two pieces of old rusty twisted steel rio bar,you will notice that one of them is bent,it's what dave used to start that contakerious(sp) high compression 150 that backfired every time you flick the prop.