Back in 1981 I fitted the engine out of my '78 SR500 Yammie into the frame of my '78 Husky 390 AMX and raced it in C grade MX and a few club enduros for a while. I never called it a HL though, always an Aberg replica.
I still have it in the shed, but it doesn't have an engine fitted at present. It also has a set of IT forks fitted instead of the YZ465G forks that I used when I first made it. All of the bits of the 390 AMX are still in boxes in the shed and I bought a 390CR frame a few years back to rebuilt the Aberg on so I can put the AMX back together with it original frame.