Its pretty dirty, but that state of affairs is also pretty typical for a 60 or so year old 235. I would look at the bearings and see what the condition looks like. If they are not terrible, I am not sure there is any downside to scrubbing that motor up really well, putting it back together and seeing what it does other then the time, effort, and a gasket set. These motors are pretty rugged in that respect and a lot have run in a lot worse condition.
the rub for you is that you are looking for the best of both worlds, scrubbing it up, putting it back together and reliability that would be sufficient to drive to the NSRA nats. You might get it you might not.
