Whoa. That's an ambitious project. I've had one of those 212R amps. I sold it pretty fast. There's a goofy design in the overload sensing circuit which I couldn't fix, so I disabled it. It would indeed make a good parts source for using the cabinet and chassis, though. I would strip everything else out of it and build from scratch. Is the chassis heavy enough to support the transformers? Does the front panel line up with any of the repro BF fender panels?