great build yes... but use iron heads and numbers go down... the advent of nice aluminum heads do wonders for these engines. i would LOVE to have a monster like that... when this ole 400 wears out i will have to keep MRL phone # handy.
They only go down if the builder doesn't match the parts well. Material has NOTHING to do with flow, unless you're talking about the time required to port it. That engine is roughyl 1.16hp/inch. That level of power is made fairly easilly with iron as long as the builder has some talent. But in terms of economy, aluminum will do a good job, for a little more money, and have plenty of room to grow, plus provide the weight savings. Win Win Win. but that doesn't mean iron can't do it.
