Here's an unusual engine that I saw run at our local dyno the other day....
This is a Jimmy 302 from an old GMC truck. It has a Rotrex supercharger and a custom EFI intake. (the air cleaners are not functional - I guess they're there just to confuse people...inside them is a 180 degree elbow that connects the throttle bodies to the duct from the blower, which wraps around the front of the valve cover). This winter I'll be installing this beast in a '37 Chevy coupe street rod....it's going to be a tight squeeze.
It has a neat sound....reminds me of an old v6 2-stroke Detroit. Unfortunately, I couldn't stick around to see them get the fuel and timing worked out. They did eventually get some acceptable numbers out of it. It was something like 360 HP and 430 Ft/lbs, and they never pushed it past 5000 rpm.