4.0L SOHC Intake gasket leaking?

[toy4x4]

Ok I've been searching the web and sounds like my buddy might have intake gasket leaks... However his intake looks different than others could it still have the leak or is his intake an improved version?

His intake looks like this...

Others look like this...

His is a 98 Eddie Bauer Explorer 4.0 SOHC like top pic.
Anyone know what year the intake changed on the 4.0l SOHC and did this eliminate the intake gasket leak issue?

 

[2000StreetRod]

not stock

The stock 1998 SOHC V6 upper intake manifold had the variable induction system (VIS) and looked like the one below. He has the one piece intake manifold.

Since his valve covers have also been replaced (oil filler tube on passenger side instead of driver side) he probably has a replacement engine from a 2001 or later Ranger or Sport Trac, 2002 or later Explorer, or even a 2005 or later Mustang. I don't know what year Ford switched to the electronic throttle body with the intake manifold inlet port and EGR port in the rear (maybe 2004). Anyway, I think the one piece intake manifold gaskets can still develop a leak but it's not as common as on the stock two piece manifolds.

Below is a 2004 Explorer one piece intake manifold with the passenger side inlet port.

And here's a 2006 Mustang with the electronic throttle body, one piece intake manifold with front inlet port and driver side oil filler tube.

My guess is a 2002 or 2003 Explorer engine but I'm not familiar with them.

 

[toy4x4]

BTW that's not the actual picture of his engine but I know his is that type intake. Can't remember which side the oil filler was on... Perhaps his engine is not really a 98 model? I will try to get another look at his tonight or this weekend.

 

[01funk]

How can i tell if mines a dohc or a sohc can i tell by vin and if so how help please