Magnum block versus la oil filter adapter

After trying to install an la block angled oil filter adapter on a magnum block I found that the cork gasket that goes on the bolt between the block and adapter can't contact both the magnum block surface and the adapter surface to seal properly. The Magnum blocks have the center surface where the bolt threads in cut even with the outer gasket surface. The la blocks have a raised center. The difference in height causes the problem. I am going to shim the gasket with washers and thin bushings to solve this problem. Any one having an la block could you please Measure the height of that center surface to establish the shim height needed for proper gasket crush? Moderators, if you could ad this to the tech section it would help others.
Credit LeeinRI for the info on the block difference. Thanks Lee!