TA Dreaming

Quick question for those that know. There are five ports on the bottom of the intake manifold under the metal cover. Are all five supposed to be plugged or is the middle one supposed to be open? Any ideas on why these ports are even there in the first place? Thanks Trey

97 6SPEED Z

Trey, those ports are there to remove the core sand used to form the internal structure of the intake manifold during the casting process. After the raw casting is "shaken out" and the core sand is removed, those ports are later threaded, and the plugs installed. And finally......yes, to function properly all five(5) ports must be plugged. Looks like you're missing one?

wrd1972

Mine has all five plugged.

TA Dreaming

Well, the intake that is on the car has all five plugged. I figured they were for casting purposes but was not going to assume. I have also discovered they are the IAC passages and vacuum passages.

The problem I am having is that this intake is on a gen I SBC. I am using it as a FI manifold. System is working great excpet for too much crank case pressure and oil comsumption. The crankcase pressure is due to the fact that the heat xover ports are not completely blocked by the manifold. This I didn't notice right off. I will figure something out there to block them off.

That leaves me trying to figure out how oil is entering the intake manifold at the front. The two holes at the bottom just behind the TB wall is where the oil appears to be entering. I am running a PCV in the manner run on C4s and I have no vacuum lines connected to the TB. So that's really the only thing I have left to discover a solution to.

Thanks Trey

This car smokes constantly too from the oil entrusion. This isn't a quart every oil change consumption issue. Car has maybe 20 miles on the odo since this intake went on. So it's significant.