I'm in the process of replacing the rubber transfer case mounts on my '60. I removed the eight 9/16 bolts that were holding the mounting brackets. I noticed that they were fine thread number 5's. Is there any reason I couldn't replace these bolts with number 8's coarse thread bolts? Why did the manufacturer use the fine threads? I know that the number 8's are stronger, but are they not as flexible or maleable as the number 5's?