I have had this thing sitting in a box for years I've gone to fit it and Notice it has two spacer options. The pic shows the flat one installed and the gap it leaves tightened up. The other one closes the gap but is it too much. I could machine the second one down but before I do I'd love to see some instructions . Or if they had a choice of different width spacers originally.

I found this image on google wich looks like it is  somewhere in between the two I have . It would be great if someone who has one could measure it.