Is it completely necessary? I'm thinking yes or I will get leakage from nearby bolts thorough intake? I can't believe I did this, but I assembled the while engine and they are sitting on top of my car.
Sorry, this is on the intake gasket, not head gasket. It is the very center port and with my felpro gasket it either had a insert to block, or an insert with openings, but separating the bolt holes.
The insert will have two benefits: one is to prevent the hot corrosive exhaust gases from eating your aluminum intake. Two, it will keep the intake cooler, but that's something you may not want when driving it in winter. I use em, seen too many nice aluminum intakes eaten up by the gases in the cross over.
Here in the warmer climates, a lot of folks use the blockoff plates. I don't know how cold it gets where you live, but the only real purpose of the crossover is to heat the intake for reduced emissions! It does help drivability in cold climates. You should have two sets of plates. Ones with a port in them and ones that are blockoffs. If you are interested in performance, use the blockoffs. A cooler intake will keep the air denser.
Unfortunately this is my daily driver and it gets very cold here, otherwise I would. We also have some serious altitude here in utah so air density seems to lack. That is why I plan to eventually add a supercharger or turbocharger. But for winter's sake I think I need that crossover.
