There were a couple contributing factors which limited the numbers of the 508's. The first being it had an inferior riveted front bearing plate which was prone to shifting about. That of course wasn't conducive for it's undersized armature's overall health. Mind you that this all happened during a model change during a recession year. I think they were being just a little cheap, but they quickly resolved that issue with the later 508. I think it was one of Kirby's rare lemons; as from this model Kirby introduced its rebuild program to stave off any backlash - that would seem logical. The early 508 which I have is identical to a 505 with the only exception of the color scheme. There was not a whole lot produced, and so many to fell victim to the rebuild program, that to even find one is no small feat - especially one unaltered as the one I have pictured. Even on eBay I've seen rebuilt 508's go for good money, for there is so few of them and therefore are highly sot after. Your belt lifter is original to the later 508 and is of the heaver gauge. Even all that has been said you have yourself a very rare Kirby, and congratulations once more. Post pictures of your progress, because I'm sure it's going to be outstanding!