'99 Volvo Penta 5.0 GL valve cover leak question

[Augoose]

All,
I recently finished installing new aftermarket heads from Marine Engines 4 less. On the port side of the engine my original OEM valve cover is not sitting flush and I'm leaking oil from the lowest corner at the aft end of the cover. I used an endoscope and I can see a 1-2mm gap between the bottom surface of the valve cover and the top surface of the head, despite being properly torqued. I removed the valve cover (which can be done without loosening or removing the manifolds or risers BTW) and it does not appear to be bent, twisted or damaged in any way. It is not leaking through a rusty hole in the cover itself. It is definitely not seating correctly on the head.
When I reinstalled the cover just now, I noticed that it rocks a bit on what appears to be the framework for the PCV valve (circled in red below). I've tried to adjust the fit every which way to see if the cover sits down nicely but I just seems that there is some sort of obstruction between this OEM cover and the aftermarket head and it feels like its in the vicinity of this piece.
Anyone run into anything like this? I've got an email into Marine Engines4Less but wanted to ask the knowledgeable folks here too.
Thanks!

 

[ESGWheel]

Here is my suggestion:
Start by placing the cover on a known flat surface. See if it rocks or is somehow bent. This assumes the red circled item is recessed from the plane of the sealing surface. Assuming all good, get some plumbers putty and roll a thin cord with it like this link. Place this thin cord around the bottom edge of the PCV bell. Put on the cover and then remove. The putty will be the tell tale to show you if any interference > if the putty is squeezed out completely in one or more area, then you have interference.

 

[Bondo]

Ayuh,... Did you try turning the cover, end to end,..??

 

[Augoose]

Here is my suggestion:
Start by placing the cover on a known flat surface. See if it rocks or is somehow bent. This assumes the red circled item is recessed from the plane of the sealing surface. Assuming all good, get some plumbers putty and roll a thin cord with it like this link. Place this thin cord around the bottom edge of the PCV bell. Put on the cover and then remove. The putty will be the tell tale to show you if any interference > if the putty is squeezed out completely in one or more area, then you have interference.

I'll try that, thanks!

 

[Augoose]

Ayuh,... Did you try turning the cover, end to end,..??

I didn't as that valve cover has the oil fill hole and cap in the front. I inadvertently wrote port side in my original post but it is indeed the starboard side valve cover. I will flip it around and see if it sits down level. Thx!

 

[Augoose]

Just to follow up on this thread, I tried using the great suggestions of plumber's putty to identify clearance issues and swapping covers around and after some adjustment, the original cover sat better but still not completely down on the head. I thought valve covers were all the same but it turns out that there are subtle differences that I wasn't aware of. For example.....
My VP 5.0 GL has the valve cover with the oil fill cap on the starboard side and the oil fill cap is towards the front, while it seems most GM references and covers I found have the oil fill cap being on the port side and towards the front.
When I ordered what I thought was an exact replacement for my starboard side cover, what arrived was opposite. At first glance I thought the bolt holes ran through the center of the cover but in fact they are slightly offset, so when I tried to install my new starboard side cover with the oil fill cap towards the front, the cover wouldn't fit as the bolts are slightly offset. I flipped the cover around and put the fill cap towards the rear and the cover went on fine, no leaks. This explains why when I tried to fit the port cover on the starboard side it fit, but when I put my original starboard cover on the port side for testing with the oil cap forward, it didn't fit. I had no clue the bolt holes were not down the center. Hopefully that helps someone else out.
I even ordered this cover from a marine supplier and it was supposed to be a match for the VP 5.0 engines. Why does VP run the oil fill cap on the other side?
From what I read it doesn't matter where the fill cap is, correct?
Thanks