Conversion to 88-95 serpentine question

[reb162]

So, in preparation for my crate engine, I made the decision to go with an 88-95 Chevrolet truck serpentine system rather than the original multiple belt setup.

I got the brackets and mounting bolts off ebay for a 1995 Chevrolet C1500. It came with no tensioner or idler pulley so I purchased those for a 1995 c1500.

ACDelco 38108 Professional Automatic Belt Tensioner and Pulley Assembly

ACDelco 15-4957 GM Original Equipment Drive Belt Idler Pulley

On the bracket with the belt tensioner (P/N 10118751) the idler pullet fits fine, but the belt tensioner appears to have an issue. The bolt hole in the tensioner appears to be too large. The bolt measures as a 12mm 1.75 thread bolt and threads into the bracket just fine. However, the bolt is very loose in the tensioner, more than I'm comfortable with. Anyone else have this issue. Was there originally a sleeve in the tensioner?

The bolt mics at 10.79mm at the shank where the tensioner would mount. The hole in the tensioner mics at 14.21mm

Any ideas? Do I have a mismatch in parts somehow (all part numbers check out good for 1995 c1500 by my checks). Am I missing a sleeve?

Appreciate any help.