One more thing - I don't know how Lee calculates the compression ratio on two stroke engines -so the noted 6.86 compression ratio seemed a bit odd to me .
(back when - that is about the compression I used on my Olds engine with a blower giving 12 lb boost )
On pipe tuned engines - really high compression is not good -
On the two strokes we have done for pipe tuning - we always lowered the compression -on glow, especially .
If the compression on glow was high, - the engine really heated /lost power
So far -on my gas engines, the spark ignition seems to control any problem -as long as the mix is set right .
the "high compression" on the ZDZ never really acted "high" and the compression RATIO (if calculated from BDC ) would be high but if figured from closed exhaust port - would be quite different - and different on each engine design they have .
Some of the group have as much as almost 25 degrees less exhaust open period.
I like the engines - as I am still a bit of an engine fancier - have been since I built my first 274 ci in flathead Ford
that has been a couple of years -----