Well, about 1 1/2 weeks ago we finally got a new clutch sprocket, and clutch spring. The notch in the sprocket isn't large enough for the key and when looking at the new vs old one, you can visibly see the difference. Per their suggestion, I attempted to file it but the metal is so strong. Honestly, it didn't look like it would resolve the issue. I spoke with the vendor whose been responsive, and we started to dig further into the engine.
On Monday he had me take the head off where we discovered the actual issue and why it ran so poorly. His supplier was the one who assembled the head and they put the piston on facing the wrong direction. He was super nice and took responsibility, although it was the other shop who made the mistake.
Oh well, stuff happens and I'm honestly just excited it all wasn't somehow our fault. I was told today they are shipping us a new engine. I just hope we can actually get this one running, although of course now heading into the winter months... But if we can get it running decently, that'll be super exciting!