Welcome aboard Kurt.
We just pulled ours apart as we were loosing coolant as well. If it was just rebuilt, it should come apart relatively easily (not yet full of krud). we just had ours welded/machined at a local machine shop when we had a small hole develop pushing coolant into the ocean. very economical if you can pull it yourself.
I've heard rumor of someone re-routing to an aftermarket cooler but I don't know where to point you for that. It really seems like a pain since you'd need the exhaust and intake manifolds fabbed.
Also, are you sure you're not just pushing it out the cap? Our coolant level at rest is lower than you would think. Finally at 2300 rpms, that's pretty hard on these. I think red line is 2450? maybe that's just on mine. Someone more knowledgeable will step in, I'm sure.