I believe I fixed the head gasket issue. One of the head studs was threaded into a helicoil. I had a guy CNC machine a threaded insert and am now running a copper gasket.

Also, I noticed a guy on CL parting a z400, so I got the front spindles, hubs, and rotors on the way to change this bike over. Should be a big improvement since these factory parts are steel and the z400 ones are aluminum. Them I'll get better brakes since the rotors are slightly larger and I can run yfz dual pistol calipers