[torqhead]

I've got a 455 that has an oil leak at the rear of the oil pan. It's a 74 motor and has had an after market 7 qt. oil pan installed. This was installed when the motor was rebuilt. There is currently a PCV in the valley and each valve cover has a large filter on it to ensure any pressure in the block is being expelled. The latest try, 5th time, the shop that has been working on it found two different types of rubber seals that can be used on the back half circle shape that seals against the rear main cap. He cut slots to allow the rubber seal that had 5 retainers to be installed hopefully giving it more support. After running the engine, never exceeded 3000 rpm, parked the car and discovered it leaking again.

Has anyone experienced this before and have any advice on how to resolve.