I looked in the the archives used the search function and called all my known contacts. Nobody can seem to answer this. I just received a water pump pulley from Ebay for my 402. The number is 3976059AO. The measurements are 6.219 dia, 1.975 depth, 1.9125 back-spacing. Is there supposed to be a reinforcement welded to the back of it? By the measurements i provided do i have the right pulley? It appears my other pulleys don't line up with the water pump by 1/16 of an inch. I could shim it 1/16 to get to line up. The question is should i have to? This is on a 3937787AC crank pulley and the water pump is a 3989811TX. Everything lined up perfectly with my aftermarket deep groove repros. Also on the back of my aftermarket deep groove water pump pulley there is a 1/16 reinforcement welded to it. This was from a 69 375 horse deep groove pulley kit. Any help would be appreciated. Thanks in advance. Ron.