Belt Question...

This is really stupid, but I am curious so I am going to ask. AM I the only one having trouble with new belts? I got a new alternator belt not too long ago. The old one was stretched and the alternator was against the fender well and could not tighten any further. So I got a new one about an inch shorter. Installed it, tightened it good. I noticed the last couple of times I've driven the belt squeals in brisk acceleration. So today, since I was under the hood installing my carburetor heat shield, I tightened the belt up. Is it just me or do these new belts stretch too easily? I don't remember ever having this problem before. I can put the pry bar on the alternator and just stretch it like a rubber band.
Yup, I noticed my last belt stretched easily and I'm not getting any stronger. BTW, did you put a heat shield on the Weber 32/36 carb? I remember you had that on your list. Let us know if/when you get it. I'd like to get your opinion since I have the 38/38 carb and was thinking about trying out the 32/36. Thanx.