Don’t think anyone was having difficulty determining if it was a B or RB motor, I think the question was why doesn’t the casting number show up anywhere. I didn’t find much info despite the comment that info was out there, much like the OP (who started the thread 2 years ago).
My only add to the info in this thread was that (assuming I wasn’t fed a lie about the motor I bought), this odd casting number block did in fact come in cars as well. Not just some industrial application.
