Vacuum Advance suffix Numbers

SuperDave

I am trying to obtain a vacuum advance for a IAT distributor 4009B.Should be for a 54 262 or 308. My research says the proper number is IAT-2023. I hope that part is right. (?)  I have found several advances but I don't know what the suffixes mean. they range from -R, -RG,  -RN, -RM, and -LL.

 I suspect the suffix defines  the maximum advance. Anyone have some Autolite reference charts?

DavidC

Dave Kostanszek sold me mine, he may still have some

SuperDave

Thanks Ken...The" RN"  is what I needed. I wish I had an old Autolite reference. Sometimes I run actross parts and don't know the application.