I went to fire up my motor today, but I got the wrong belt. My engine is a 5.7, and it has one serpentine belt that drives all the accessories. I wanted to know what size belt I needed to fit properly, again it has no smog pump, and it has an ac delete pulley. Thanks

 

best thing to do is take a piece of rope and loop it the same way the belt is going to be . Just make sure you take into account the belt tensioner

 

I feel like an idiot, I just ran the belt another way and it worked. I didn't even tell the guy I knew at Advance that I had no smog pump. I don't think I ran it the way it comes stock, i'm worried about the belt rubbing right after it comes off the tensioner. It seems a little too close.
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The part number was 6pk2490 dayco, it also has 5060980 in bigger letters on the box, if anyone cares. I thought I needed the 96.8" belt, and I don't think this is, but it fits.

 

on my 90 rs 305 i removed the a/c, smog pump and tensioner and i believe it was a 50" belt.