As long as the aircraft was never registered (N-Numbered) then you have no issues, at least as the regs are concerned. Weight and fuel capacity are the key points. The other points can be ignored as a PPC (max airspeed, stall speed, etc.).

On the aircraft itself, you may need to look closely on where the canopy is mounted to get a good weight and balance. Some rebuild the aircraft with a shorter frame to loose some weight and take up the space from the 2nd seat, but that pushes the center of gravity backwards from the original position.

Hang the aircraft from something strong, get in the front seat, and have someone measure the angle of the blades from vertical. You want to have the same angle when you are done.

If you are not reducing the length of the PPC, you can measure the height of all the wheels above the ground and match that afterwards. But if you shorten the system, matching the wheel height can change your prop angle.