It's even more of a "dice toss" with an A64 that has the IHS removed. The two screws down the centerline provide good retention in that axis, but suck royally in the other axis with the weight and tubing torque causing it to vary all over the place. It's probably the number one problem trying to get reproduceable results from one mount to the next. When you can reach in and press each of the four quadrants of the block and get four different temps, that's aggrivating, to say the least.
Hoot