RE: K & B 7.5 DF on prop ?
kewl...... that looks like one of the modified engines that were sold for a while - If I recall properly Tom Cook sold them configured like that. Has an OS carb on it - BIG carb!! Was a huge improvement over the K&B that was available with the Perry.
I would not try to bypass the pump. The engine will not run well with that carb without the pump. It simply can not draw enough fuel.
The pipe is set REAL short. Looks like about pipe setup - around 10 " or so ??? In that case, its going to need a very small diameter prop or the engine will not run properly (unless you make the pipe assembly longer). You may want to try one of the APC carbon QM40 props to start with. Let that sucker turn up.
Bob