I took my belt back to GM today to get a shorter one. No luck. They cant get a belt by the length. The 5.3 a/c belt is 960mm long and it just does let the tensioner bottom out. Any ideas? Turns out, GM cant look up a belt for a LS1 powered 86 silverado with a 04 5.3 a/c unit and a balancer with extra groves machined in. Who knew???