Had to replace the thermostat and outlet housing on a 5.2. Requires removing the front bracket that holds the alternator, idler pulley, and some other accessories (see pic). After putting everything back together, noticing the belt is too short. this is the exact same belt I removed before the service (955k7). now I know there's three options for belts on this engine: one with A/c, one with dealer installed a/c, and one with no a/c. I know there's a longer belt option (1005k7) should I just try that belt? Or did I miss something in reinstalling the support bracket?

 

Are you reusing the old belt or installing a new one? Could be you are routing it wrong... also notice that the tensioner has to be pulled inward to give enough slack slip the belt under the idler pulley.
click the link and scroll down just a bit for belt routing diagram

http://www.onlineautorepair.net/2010...-belt-diagram/

 

i am using the same belt I removed. Followed the routing correctly, and even with the tensioner maxed out, still needs about 4-5 inches. Which is why I'm thinking there's a possibility something was shifted in reainstallation, or I can just try the longer belt option.

 

Sorry, somehow missed you stating that the belt in question is the one that came off of it to begin with.
The one thing I can think of is that maybe your belt being short is because the a/c may have been bypassed before and it's not the right belt. have you tried the option for routing it with no a/c to see if it fits?
Other thing is take the belt to the parts store and match it up to the choices you have available...

 

also considered that too. Tried bypassing the a/c and had too much slack. Picked up all three sizes of belts for the engine and will start comparing later today

 

You're routing it wrong.

 

+++ 1 ^^^^