The engine will do fine in the Yak.

To minimize cowl cutting, you should consider mounting the engine inverted.

You WILL have to cut the cowl, but with the engine inverted you can make one large cutout on the bottom that serves multiple purposes.

E.G. it can both permit the cowl to be attached, and provide enough clearance for the muffler extension.

At worst you can also use an O.S. Extension tube pipe to bring the muffler outside of the cowl or further back too.


Another option would be to use a Pitts Style muffler and mount the engine inverted.

But this would require BOTH a side cut and a bottom cut.

I would go with the inverted.