Mr.MazzaGlad to hear your getting your engine fixed. For what it's worth, a large part of Ace's head rework involves improving the gas flow thru the heads ports.This is not a matter of simply enlarging them by removing material. It is more, reshaping them so the gasses flow smoothly without dead spots and turbulence.Knowing what the best shape and size should be is the trick and only thru extensive airflow testing can this be found. Ace has done this testing and knows the answer.Anyway, hopefully you will get your engine back together so you can get back on the road.
Although I like your list it didn't include something I think is very important for improving the reliability of a iron barrel.A sleeved alloy cylinder. IMO, one of the iron barrels biggest downfalls is its iron barrel.Cast Iron conducts heat very poorly. That's why you can have a cast iron frying pan that's hot enough to fry an egg while you can still grab the handle without badly burning your hand, at least for a while.Cast aluminum conducts heat about 4.6 times better than cast iron. (This value in the US is usually given as a BTU/hr/sq. ft./degree F/ft value. Note that distance is one of the important factors.)That means for any linear distance 4.6 times as much heat can be conducted away from the piston and cylinder wall per minute or second.Although the alloy cylinder has a steel liner in it and the steel liner is also poor at conducting heat the fact that the liner is thin means the heat doesn't have far to travel at the slower value before it gets to the aluminum which rapidly conducts the heat away.All of this results in the iron barrels old nemesis, heat, being dealt with so the possibility of overheating and piston seizure are greatly reduced.