[YENKO DEUCE REGISTRY]

I'm assuming that the JJ was the engine application code? If so, it doesn't surprise me at all that it would be written on the engine under/over the orange paint.

This practice has been documented on a few Yenko Deuces, except that it's written on the sides, in yellow, and upside down. The location and color differences also do not surprise me, because your L89 engine was a Tonowanda engine for a Norwood car, and the Deuces have a Flint engine for a Willow Run car. So, I would expect some differences in the practice due to different engine & assy plants.

Additionally, we have found white 'X's on the ends of the cylinder heads, and blue paint on the head bolts. Both colors are under the orange engine paint, however, the CTB is on top of the orange.