10-Bolt / 12 Bolt Control Arm Difference

	The rear upper control in the top of the picture is a stock 10 Bolt control arm.The rear upper control in the bottom of the picture is a stock 12 Bolt control arm. As you can see, the 12 Bolt arm is notched and reinforced below the bolt hole.These control arms are the same for all 1968 through 1972 GM A-Body cars.
	This picture shows a close-up of the 10-bolt upper arm.This arm is exactly the same as the 12-bolt arm but it was not ground down and not reinforcement plated has been added.I can modify your arms to create a 12-bolt arms for you (see the process)
	This picture shows a close-up of the 12-bolt upper arm.This modified arm was only on the drivers side. There were no clearance issues on the passenger side.There’s a reinforcement plate spot welded over the hole from the factory. This was done because the 12 Bolt rear end chase is larger then the 10 Bolt rear end. The arm was ground down to create clearance needed for the rear end, the plate was spot welded to the arm to restore the strength. I can do this modification for you (see the process).
	This is a 12-bolt upper arm on a 12-bolt rear. Not shown is that the passenger arm. These (passenger) arms are the same for all rears, no clearance problems.
	This is a Non-12-bolt arm on the 12-bolt rear. Note the interference with the carrier housing. I can fix this for you (see the process).