The top idler on 3.2's can be replaced with a 99-13 GM truck 4.8/5.3/6.0/6.2 idler pulley. It's around $30 and it's a whole new assembly. A lot of LS engines regularly see 7000rpm so I don't think RPM will **** it but we'll see.
I think the tensioner idler from the same trucks will work on the...