Several years ago I replaced the stock iron heads on my 512 stoker with Edelbrock aluminum performance heads. The main reason that I had done this was that I had a horrific plug fouling problem and after trying every trick that I could uncover finally in spite advice from many, decided to swap out the heads as I was convinced that it was a sealing problem between the intake ports on the iron heads and my six pack intake.

I(we) had pulled the intake 3 times, closely examining the turkey pan metal gasket looking for any signs of oil being able to get into the intake ports from the lifter chamber to no success. Also doing the trick to ensure that intake had no gaps in contact with heads,,,as per the most obvious cause of perhaps milled heads with no corresponding planing of intake. All look ok each time.

Nevertheless replaced heads with Edelbrocks,,,ergo no more plug fouling and engine performance was outstanding.

However, ever since this swap, I have been plagued with oil seepage between my Mopar Performance aluminum valve covers and the heads,,,,only at the rear third of each cover at header side.

I have tried 3 or 4 different gasket sets, from cork to Moroso to Mr. Gasket. Finally installed a set of Superperformance gaskets,,,following instructions to a T,,,using silicone on valve cover side, installing but not tightening too much, waiting 12 hours and cinching down,,,although on aluminum heads being aware that if torqued to iron heads specs, I could pull the threads.

So being me, I assumed all would be well and off I go Saturday morning for a Mopar Cruise event,,,,and not to long I was aware of the familiar odor of hot oil cooking on headers.

So now I am saying, so much for Superperformance gaskets too. But this time I did a very close inspection postmortem.

These photos say it all,,,,note the head imprint on the gaskets at the bottom, header edge verses the intake edge. Of course this is where you need the most sealing as this is where the oil puddles.

It appears my problem is not my valve covers, nor my gaskets,,,,but an extremely poor made is on God knows where job of machining an adequately wide platform on the contact to valve cover edge.

2 photos are of radiator end of heads,,,all is well, 2 are of firewall end,,,very narrow edge,,,where leaking/seeping occurs.

Any advice as to where I go from here? I do intend to Edelbrock to hear what they have to say.

Actually the only reasonable relief I found in leaking was to take the least expensive O’Rielly Felpro gaskets and slather them with black silicone. Not the best solution or even a decent one for ease of maintenance. Pulling and replacing my heads does no appeal,,,but I suspect that is where I am heading.

Interesting. I don't see much oil puddling, and it looks like quite adequate crush on the gasket, and I've had narrower rails that sealed just fine with cork gaskets.
But that area was the intake side. So, throwing some darts...
Have you measured the height of your hold-down bolts to make sure they're not holding the covers up a bit?
(Not that I see any witness of interference, but I'm wondering about heat expansion.)
I haven't experienced that problem with Eddy or Stealth or stock heads, but I have had a set of MP covers that barely provided enough sealing area.
The MPs seem tall enough not to interfere with roller rockers, but with stock covers & rollers I've had to fab spacers for the covers.

Have you checked the cover for true??You have tried enough gaskets and have the same issue.All my gaskets are SUPERPERFORMANCE except exhaust & head gaskets

Interesting that your comment regarding a decent seal with a narrow platform,,,,matches my comment that my best outcome was with cork,,albeit using a load of silicone.

Yes I have assured that hold down bolts are not bottoming out before gasket compression has very well occurred. I remember very well the experience that I had several years ago with rear main seals. I had purchased a brand new set of pan bolts from Mr. Gasket,,,installed them, ended up with a massive leak at rear main. Started engine flywheel cover removed. Had a look see up the flywheel, looked like rear main leak,,,,closer examination was that rear of pan was cause of leak.

Apparently Mr. Gasket did not know,,,,nor did hardly anyone else for that matter,,,that the 2 pan bolts that go into rear main retainer, are per Mopar specs must be shorter than the remaining 18? pan bolts. Mr. Gasket packages all bolts at exact same length. Therefore rear main two bottom out.

I do have more than adequate clearance between Harland Sharp rockers and valve cover.

Imprints on gaskets at the head side of them show substantial crush all about the valve cover,,,just very narrow at the rear of each.

Cannot understand why radiator end of heads has a valve cover gasket platform likely twice as wide as is firewall end. Would Edelbrock does this deliberately,,,would seem odd as the rear of the head is where the majority of pooling is likely.

Has anyone a set of these heads not mounted, that they can have a look see if the rear platform is much narrower than the front platform as I see on mine?

Do any of you run your valve covers with no gaskets,,,only using a bead of silicone? Likely this would make them very difficult,,,,and time consuming whenever valve covers must be removed.

Yes I have. Even with iron heads, I had a very slight seepage at rear of driver side. A dab of silicone there always took care of it. These covers are not military grade machined so this cover was prone to seep.

I did dump a bunch of flour on a sheet of glass, sat each valve cover on it. There was contact all around each cover,,,,by examining imprint in flour...however the imprint was a bit less defined at rear of one of them.

However a gasket should take this up,,,,and in fact my gaskets are again imprinted very well when examined upon removal of valve cover,,,,,just very narrow at leak points.

But as I look at crush imprint it should be sufficient,,,,but where head platform is narrow,,,it almost looks like it was dremel tool ground down where it is so narrow,,,looks like tooling marks here,,,almost as if machining a bit more clearances for base of valve spring. Which by the way triggers a thought. I had a machine shop setup heads and also install ‘beehive’. Wonder if they may have done a bit of clearance fine tuning. Each rear spring is pretty close to pocket at edge of head.

Mopar Performance valve covers are too wide to seal very well on most heads. You can prove this to yourself with a tape measure. Once you understand the problem you can try and fix it. The only gasket that I've every had any luck sealing with a MP valve covers is the Fel Pro 1612. The 1612 is really thick and it will stand up to the twisting action caused by the valve cover being too wide. If you use a rubber gasket such as the Moroso one it will just twist and shear off. Thinner gaskets will also twist and fail. Good luck, you'll need it. I eventually tossed all of my MP valve covers and found some that were designed correctly. Once I started to use valve covers which were correctly designed all of my valve cover leaks stopped.

Got a long straightedge an some feeler gauges?
Lay the straightedge on the VC rail on the head, and also the VC - and see if the surfaces are dead flat.
I don't recall if the MP VCs have a rib around the inner perimeter, but if so, that could be twisting the gasket.
When I mentioned hold-down bolts, I was referring to the rocker shafts; check the height of the outer bolt heads vs the raised lugs inside your VCs.

Heads are bisexual. I have Indy covers (no logo) on a set of Edelbrock Performer RPM heads. The only gasket they didn't like was the blue, rubber, Moroso one with the steel shim. I tighten them "palming" a 1/4" drive ratchet moving inside out like a head or an intake. I go until they stop turning going over all the nuts about three times. Studs are the way to go if you have room to lift them off the extra inch or so. Prepare to grind some aluminum off at the distributor.

When viewing photos of firewall end and the radiator end of the 2 head photos, you will note that the firewall end exhaust valve spring is crowded very close to edge of head, whereas the radiator end is much further from the edge. Perhaps an optical illusion from photo, perhaps rocker arm placement over valve spring is giving this appearance of closer at the back.

Also the ‘lip’ where the gasket sits is much wider on the radiator end than the firewall end.

I am not questioning your assessment that the heads are Bi-sexual(having never considered the thought that I could flip heads from side to side at will), but if so and oil tends to pool and overflow the ridge banks st the rear more than at the front,,,,,would this knowledge be a worthwhile consideration when installing heads to lessen possible oil seepage or leaking?

This is somewhat above my pay grade as a somewhat advanced rookie as a engine technician, so am asking as a point of curiosity.

As my seepage is only near the firewall end of each head, as obviously from oil tracking streams on the head,,,for now as an experiment, I have slathered a dose of black Permatex silicone on the head side of each Superperformance gasket at firewall end,,,,about 8 Inchs from the end of the head.

I do have an inch pounds torqometer meter snapon torque wrench,,,picked up many years ago on EBay.

Anyone know proper inch pound torque for Mopar performance covers on Eddy aluminum heads. I would hate to pull the threads out of one of the bolts.

Try 30 to 45 inch lbs. torque for standard 1/4 inch studs and nuts :wrench : Make sure and retighten them several times after letting the motor get hot each time until the gaskets take a permanent set

Looks to me like you are running out of sealing surface in the divot by the lower right hand bolt. Why don't you just build it up with some JB Weld, and then hand file it level to the sealing surface.

Show a pic of the valve cover.. I want to see if they have a lip on them..
I had a issue with the covers leaking.. it was due to the joint at the
intake and heads.. if you notice you have very little difference between
the intake and head... I had to clearance that area so the covers could
set lower.. it was very little to make them clear and the oil ran back to
the corner so I thought that was the leak.. I had to clearance the area
all alone the intake.. if you have alum covers they could be touching
the intake and not setting down all the way
EDIT
looking at your covers you do have a lip.. I think that lip isnt letting the
cover to set all the way down at the intake
I ended up milling that lip off.. all the way around.. mine was on a set of
W-9 covers

Looks like its the junk mopar valve cover.

I'd try another pair of covers.

There is no “front” or “rear” with the heads.

If you swapped the heads side for side, what was the front would become the rear.

I built a 446 for a local guy in 2005. Used the RPM heads and MP covers......FelPro 1612 gaskets..... no leaks in 14 years.
It’s s solid cam, so regularly has the covers off.

You basically need a new set of gaskets each time you pull the covers.

Yeah, the valve covers look great but they really don't fit the head perfectly, they are too big.

I have the same heads you have. I would recommend Indy valve covers to you.
The holes usually need to be opened up slightly in those covers to fit properly (Hey, it's Indy).

My second choice in a cast valve cover is the old mickey thompson/holley type but even those are a little wider than they need to be....but they have
worked great for me.

The next ones I want to buy and check out are these Summit house brand, which to me looks very close to Indy products but nicer finished, and also less expensive.
https://www.summitracing.com/parts/sum-440350/overview/

I really like my cast MP valve covers.. I only had that one issue with
them but when I got that fixed up they have never leaked
EDIT
the wider the cover is the more you can have issues with them
running into the intake and not letting them sit down the way they
should

I bought a couple sets of intake spacers for my smalls blocks because with the raised runners of some of the better flowing intake manifolds my valve cover were laying on the intake instead of the valve cover rails and leaking badly. I really like these spacers but they need test fitted and some pushrod clearance grinding. Also some of these valve cover have the mounting bolt angles off small so that needs matched to the spacers. I black silicone these right to the head and then lay my gaskets and valve covers on.




http://www.medicemfg.com/products_get.php?c=Valve%20Cover%20Spacers%20-%20Mopar

I experienced this a few times. Eliminating any warp or binding issues with the intake, I found that the area of leaking can be resolved by a dab of rtv gasket maker and tightening down the problem area first. Get all the fasteners in first and before you allow the washer under the bolt to come in contact with the VC flange, tighten down the problem area first and then work your way from top and bottom to the other end. I think that some VC flex when tightened.

My stock 340 valve covers leaked on both my stock heads and then again on my Sidewinder heads at the rear where the oil puddles. So I did what Pittsburghracer did and ordered a set of machined spacers from Medice. This raised the valve cover up farther away from the puddle and the machined surfaces helped seal the leak.