i have a 1977 K5 with a new starter i installed acouple of months ago...just last week it started to make a grinding noise (like it was not fully negaging with the fly)...a couple questions:
1)what could be the problems?
2)if I need to shim anyone have a link to something showing the process?

 

I would guess it's the shim sorry don't know a of link for it I would call a parts place to find out if it needs one or size of it. Good luck

 

Yeah, I would definitely say that something is not right. Most starters come with a check block that has a rectangular cross section. It is meant to be a go/no-go gauge for starter shimming. I do not know if something like this came in the box with your starter or not...

In the past, I can remember just tossing a few shims into it and then kicking the bendix out to see how it meshed into the flexplate(auto) / flywheel(manual).