I've used the Mancini Racing seals and the stock seal retainer.
If you have studded main bearings make sure the back ones don't hold the pan off the gasket. I've had to shorten the left rear stud on 2 different engines ( I was using custom pans: one Milodon and one Chinese). The blocks weren't drilled deep enough.
Bryand
Interesting. Have you, or anyone here, installed that type of seal?
It is also important to "offset" the 2-piece style rear main seals slightly so that the edges don't align directly with the spot where the block & rear main seal retainer come together + add a drop of adhesive to the edges of the seal halves.
I haven't used this seal yet, but I will next time around. For one reason only. The factory style seal won't hold crankcase vacuum. The red seal never leaks when installed correctly.Interesting. Have you, or anyone here, installed that type of seal?