I wouldn't change it.
I always use the factory bolt plus the brace.

 

Has anyone used just the brace? The factory bolt is the one below the oil pan that is almost impossible to get out without dropping the front diff.,,etc..I don't know if I can get it back in so I'm looking to use just opposite side bolt hole with the brace.

 

Can't see you having any issues. It only has 1 bolt holding it now and doesn't have the extra security of the "fingers:" on the brace.
I considered just using the other bolt hole but ended up pulling the engine.

 

Did you have any luck using only the Melling brace ? I’m in the middle of the same job, and that is what I was considering.

 

Yes. I was very secure and went in easy. I considered trying to put the other bolt back in but once I saw how secure it was and the fact that's the vaccum side of the pump I went with just the brace. Did you get the bolt factory pick up tube bolt out?