Magnum oil filter block plate - source?

Thanks to all for the input!
I was able to obtain one…I installed it carefully with no difficulty, fired up the engine, saw no oil pressure issues, backed out of the garage, drove a few hundred feet down the road and noticed that I was leaving a STREAM of oil behind!!!

Obviously, I headed straight back and shut it down.

Because the engine is in the car, it’s possible that I missed that this plate was making contact with center boss before the gasket but it seemed secure and I didn’t detect any wobble…I don’t think that’s it.

There are some slight “waves” on the surface of the plate that mates with the oil filter gasket but they seem to be insignificant and I would guess the gasket should be able to compensate for those…but maybe not?

Any suggestions on what to check?