Jett in-cowl muffler is basically cylinder shaped, ~3" diameter, 2" height, one exhaust outlet extends another 1" straight out the face opposite the engine. Attachment is by the normal two screws, and the adapter is on the perimeter of the flat face of the cylinder. The opposite face is rounded at the perimeter, sorta bowl-shaped. If you side-mount the engine, the muffler hangs down below, exhaust outlet points out the bottom. There's just about enough clearance beween engine and muffler to run the pushrod up to the throttle arm. Very compact arrangement. There is a baffle inside there, whose arrangement is mysterious to me. Weight is 7.0 oz, a couple oz heavier than a BCM Pitts. Never got around to taching Jett vs standard muffler, but the power boost is significant.

I've always considered their engines too pricey for my taste. I usually think YS when I want high performance.

I looked at the Hobby People website and see the Magnum .91 XLS has been discounted from what I paid. This engine deserves more notice than it gets.