I use them on my own vanagons. The bolt holes are slotted, but once they are
on all 5 studs they do not move in any direction. The only thing that has to
be done (my recommendation) is 30 seconds on a belt sander (or file) to
remove the nubs of casting flash on the spacers.

I have a $15k engine and $4k transmission in my 1964 beetle, there's a time
to be a weenie about details, and a time to not worry about it. I'm not a
tightwad, but I know when you don't need more then the basics. These spacers
are 100% Fine in my opinion, so much so that I have them on 2 of my family's
vanagons.

John
Aircooled.Net Inc.