Since you cannot see the belt welll enough to measure deflection after reinstalling what is the best way to be sure you have the tension correct? I installed my alternator today...left one shim between the pulley halfs and 5 on the outside. I tightened everything down and fired her up. The voltmeter shows just over 14 volts now. I turned it off and tightened the nut a bit more and made sure the belt was seated properly. The belt feels a bit loose...I can twist it between my fingers a half turn. Do you think I am good to go or should I move all shims to the outside and see if that seems to feel better?

I always make sure I can push the belt in about 1/2in. halfway between the pulleys. This is a little like the front-wheel spindle nut. It's a feel thing and not an exact science. But it is why I've cut a really big access panel into the firewall. Life is better now. I did it without the panel for lots of years, not that it happens very often. Sucks. Especially at night on a lonely road.

1/4 " flex for every foot axle to axle with A and B belts

if too loose, it will make a slapping noise at higher rpm, and it may also squeal if you have a really heavy electrical load on it

generally it will feel "too tight" when it's right, compared to what you expect in your Chevy and what the "general repair" books say

dunno about your "twist test" - that's not how deflection is measured

13.8-14.2 V is what it should put out - all the time
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