R.I.P. Scout26
The amount of just plain ridiculously stupid stuff done on a daily basis would blow your mind.
I've seen some four cyl horizontal aircraft engines that look like they're pretty much in line. Like this Lycoming. http://www.verticalavionics.com/images/product/engine_series_320_4.jpg
Also, the sound will most likely clear out the cat, your wife and any other extemporaneous people not accustomed to military sounds and the glorious roar of a Pratt & Whitney "round" engine.