Re 5.7.....
I was assuming this was a 350...(which are 5.73547 liters!)...apologies....
Most of what I said still applies...oil leaks at rear of crank....rocker cover gaskets, intake manifold seals.....fuel injector seals....oil bypass fitting (near oil filter on bottom rail of block)....
If you are sure the engine had good oil pressure, just change oil and filter....
