The kit was designed in the 1950s. The available engines at the time were something like .35s from what I've been told. The kit box says the plane should weigh 7 to 7.5 pounds. That's pretty heavy for a 40 engine by today's standards. It seems most 40 size planes weigh 6 pounds or less.

So, compared to how it flew in the late 1950s, it will be overpowered. Compared to a modern sport plane it will be underpowered.

I do not know what a 'knurled' engine is.

My brother has a Hog with an OS 91 four stroke. It is definitely not underpowered but it does not have unlimited vertical climb capability.

I have a Hog with an OS 70 four stroke. Mine has not been flown yet, so I cannot comment on its performance.