FelPro makes excellent seals. We'll see if they stand the test of time, but so far these replacement parts, once installed, have fixed a pretty serious vacuum leak in my 2000 SOHC Explorer 4.0 engine (plastic upper and lower intake manifolds usually see vacuum leaks with these gaskets over). Time). . Started as usual immediately after installation. Take your time and be careful not to damage the plastic manifold. Easy to do if you're not careful.