Front "China wall" sealing issue on SBM

Here is a trick. Use the black RTV Gasket Maker to assemble.

No leaks

To get it apart: spray brake parts cleaner around all the RTV sealed areas. Keep it wet with brake parts cleaner for 1/2 hour or longer as you see fit.

The Brake Parts Cleaner breaks down the RTV and it easily comes apart. Whether it be valve covers, oil pan, intake manifold, fuel pump, water pump it's all the same.

No leaks, proper prep, no oil films, then use RTV Black.

☆☆☆☆☆
I was referring to contact cements or adhesives. RTVs are a piece of cake. Use contact cement on both sides of an Al intake manifold and you may damage crap out of it trying to get it off.
Cat final drive housings take a beating supporting the rear of the track frames. The High Drives should take some beating off the final drives, but that is a rough application.