what size are the bolts? with the head at 1/2" I would say they are 5/16". The crossmember and motor mounts were 3/8" bolts. If they are5/16" then more than likely they would be for the frontend sheetmetal
3/8" bolt takes a 9/16ths wrench
I know that. I just noticed the 0.5 and didn't take into account the 53 after it, and assumed it was 1/2". my bad