You can just buy a headshell from Mesa with fan and reverb tank and unscrew the chassis and transfer it. Pretty simple...kind of expensive from Mesa though. You can go other places as well but might not come with the reverb tank and fan...
Look up gts on the boogie board, you can't go wrong.
Also, Jeff Swanson of Swanson cabinets made me a head cab for my Roadster combo and it was perfect!
If you do it make sure that it's done in a way that you can't tell between it and an original head. If not, I wouldn't do it. I've seen too many of these for sale that look terrible and don't sell.