I rebuilt my 5.7L engine, all new parts, pistons .030 over everything else stock, tbi. wont start, oil squirts from oil pan gasket, oil filter under big pressure. when this resolved 1 other top end question.
RESPONSE
Sounds like there is some sort of restriction in the oil passages or crankcase. Do you have a crankcase breather and a PCV valve installed in the valve covers? Does it still spew oil out of the oil pan with the valve cover removed?
Engine Crankcase Pressure
If the engines crankcase does not have a place to vent all the pressure will build with no place to go.