If you ever go crazy some day building a racing engine with a vacuum pump remember to turn them around. Cost me a few inches on the crankcase vacuum gauge in the first engine I built using an Aerospace Components Pump.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Thanks John. I kinda thought that was the way but better to ask than guess. 

  

The lip faces the fluid you are sealing.  The rear main seal lip faces the front of the engine, the  front crankshaft seal lip faces the rear of the engine.

John - "The Hoosier Hurricane"

Putting My Engine back together. Using Best Gasket Set. the Neoprene Seal has a Lip. Which way does it face. Front of Engine or back? Getting Old. Can't remember. thanks!