Marktee

After replacing an after market valve cover gasket and oil filter housing gasket, the car started to have issues like overboost and sometimes underboost which destroyed the new valve cover gasket and oil leak from other parts of the engine.
My question is would it be possible that the after market gaskets and oil filter causing these problems or have I done something while removing and installing the parts?
I also had to remove the intake manifold to get access to the oil filter housing gasket.

Cosworth2000

Did you screw it with the proper pattern and the correct torque? This could have been the start of the problem if you didn't follow the proper tightening and toque values and sequence. I think there is another post would value cover change and there is a Youtube video that shows the step by step process. The fact that oil is coming through the gasket is my first guess that you did something wrong.

Adi-Benz

It is possible however the gaskets are low quality. Usually from kits people will usually replace everything in the kit except the gasket, they'll go buy oem