I've only seen these four. The injector stacks only came with the hoosiers. I also have a hoosiers car with the dual four barrels and no air cleaners. From what I can tell, seemingly the only engine that was supposed to be released on the Hoosier tire cars was the stacks, but I have seen two other variations, one only one time(another member here had it, I don't remember who). I got the second variation on the 'bay and it is only the second one I have ever seen of that variation. I have probably seen close to a hundred Hoosier cars in stores and elsewhere, and all but three had the stacks. Maybe someone else has some input as to why about 99% of the RR cars I have seen had the stacks.
But to answer your question, I do believe that the above four engines are the only ones installed on the 'Bird. :wave: