Seems that nowadays, specialty-car shops are at $75-$125/hour depending on the type of work.
When I've had a business deal (vs. helping or working on a buddy's deal, which of course is free) I never had the nerve to charge more than $25/hour.
I didn't charge for research time, just materials and actual labor, with the vehicle in my garage.
That wouldn't be a good business model, nor particularly profitable, but more about someone wanting to pay for my time.
That was a few years ago, and the customer was happy.
I've turned down a couple jobs since - when I had no space - and now with moving, I'm not taking anything on.