Front Wheel Rear Seal Issues

[62_C20builder]

Hello Chevy Heads-

I have run into a problem, while replacing the front drum breaks I noticed that the reals seal was leaking. I proceeded to take the the hub off a noticed that the ENTIRE hub was full of grease...that probably didn't help the leak. Anyway, I went to Napa to get the part, but they had to order it. When it came in, it looked nothing like the original and looked bigger. I asked the guy to double check it and he said it was the right one. I did not think it would fit and I was right. I tapped it in, with all the parts properly greased, and now the nut will not screw into the point where I could put the cotter pin back in. It appears to be short of the whole by the amount of extra material on the new seal. Does anyone know where I can get seals that fit?