I have the kit pictured in the first post.
Haven't had it apart other than removing the head to clean things up before run in.
The engine has the larger front mount as mentioned and 35mm intake spacing.
Long curved clutch lever.
3 wire mag.
And the newer CDI.
I have the engine in question in a Centrix cruiser frame.
Am running a Delorto clone carb , a long torque pipe and an allen bolt kit from Sick Bike Parts.
As I am new to the " Motorized bicycle " world , I have no frame of reference to compare it to earlier engines.
I have been a bike builder for 35 or so years though ( just a bit bigger bikes).....
So far my observations are:
The cylinder was spotless when delivered .
1 head gasket.
Came with ( what I believe to be ) the old style NT carb. ( never ran it )
A different style exhaust than I have seen on the exhaust posts here.
After removing the end cap the I discover'd that the cap had a short tube extending into the muffler housing 1.5 -2" and that was it.
All of the other workings of the muffler were welded inside the housing ( I assume to the forward cap ).
Running a 24-1 mix for break in .
With the stock plug.
It runs very smooth .
Almost no perceivable vibration.
Has good torque out of the hole.
Decent top end (34 mph) GPS...
Runs cool ( winter testing )
And is of good quality.
I have order'd a second unit from the same seller .
I will be adding a Fred head, some port work and a different pipe to this one for comparison .
As I now have an old Hawk engine and a 6 year old from an unknown supplier ( Funny how things tend to breed )
to make comparisons against I'll let you know what I find out.