I'm getting ready to pull the motor out of my 87GT. I know the driveshaft bolts are 12MM 12 point. I had my impact gun on the bolts and they wouldnt budge. Its not like its a small impact either its an Ingersol Rand 2131A. I was using a swivel and extension with a 3/8 Dr socket. Do you think thats why they wont budge? I also soaked them with PB blaster. Does anyone have any tips on getting these bolts out with out stripping the heads? Any help much appreciated!