Of course, being as clueless as I am, I'm not even sure what the
"shaft" is, much less do I know which would be a better size for
installing on a 387 Peterbilt. I'm hoping to order one of these
tomorrow morning from RadioOutfitter.com, but I don't know which to get:
the 5 or 10" shaft model.

Any hints?

Thanks.
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-CH
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