Nope, you're not wrong, that is the exact correct answer. You might be able to take the O-360 out of the Cherokee and sell the airframe to pay for the cost of materials or a kit to build your "dream plane", or something closer to what you want. If you know and trust the O-360, then keep it and use it in the CH-801 or Bearthawk or whatever. You can buy an old Tri-Pacer and convert it to a Bushmaster (stretched fuselage) and make a really capable back-country bushwhacker out of it. One of our HBA members, Toobuilder, has a really nice experimental Tri-Pacer project for sale cheap cheap CHEAP, that would be perfect for your O-360. It's a taildragger already, and he put a low-drag landing gear from a Cessna 170 or L-19 on it, so it has a very good chance of making 125-140 MPH with a strong O-360. I have seen this project, it is kept high and dry in a hangar in a very dry sesert climate. You could literally sell just the wings off of your Cherokee and be able to buy his complete airframe project. And be 75% done at that starting point. If I were you I'd send him a PM and ask for photos and info on that project. Four full size people and some baggage will fit in that airplane I believe.