sorry for the delay, and thanks for writing...
I build and flew the XLT and Escape years ago. Great airplanes.
Simple answer on the engine - FIRE BSE-90, Mac quiet pipe. Have Dub set it up for an 11x9 prop.
Very user friendly engine. No bad habits. Verfiy the header rise size when ordering the engine/header/pipe.
If you search in the Classic Pattern forum you will find a couple of XLT and Escape projects with this setup.
On the PHX 7, a different choice there.
That was designed before the "big block" .61 engines. Or rather in the transition when the Webra Speed and OS 60FSR were first hitting the scene.
The Hangar 9 P-7 is designed for the "Small block" .60 engines.
The jett engine you would want is either a Jett SJ-56LX with a full size pipe, or a SJ-60 with the jett-stream muffler. Prop selection depends on the engine and how you want to fly. But figure on a 10.5x7 (if you can find one), or 11x5. You want the engines to turn up.
The OS 55AX with a jett-stream -11x6 prop is very good too, and I also recommend the Evo 60 setup.
Bob