Maybe try some threebond, you can buy it from a mazda dealer R2Y110431. Best sealant i've ever seen, wipe the surfaces down with lacquer thinner first to get the oil off. Its the only thing that will seal a rotary oil pan, and you need a mallet to break it free later on.

Although I do not have the intake caused leakage,,,leaks are on bottom side of covers,,,the spacer idea is intriguing as would raise cover up higher so lessen tendency for pooled oil to leak.

However it seem you would need 2 gasket sets,,,and would the spacer seal against head any better than valve cover currently does.

I do like the appearance of the Mopar Performance covers,,,,looks a bit more Mopar stock than some of the other perhaps better machined covers.

I currently have slathered permetex black about as I suggested in previous post,,,now setting a couple of days, time to take it out for a drive.

I also am planning to call Edelbrock to find what they have to say on this.

Rear main and valve cover leaks go with the game I guess,,,finally got the rear main taking care of,,,knock on wood.

Thank you all for your suggestions.

As noted in previous post, I determined the places that my covers were leaking,,,,oddly with the superperformance gaskets on head side of gasket whereas other brands leaked between valve cover and gasket,,,,not using sealer except a very small amount at bottom rear of valve cover on valve cover side of gasket.

I now have throughly cleaned the head ‘ridge’ with carb cleaner and from rear of head going forward about 10 inches, I ran a bead of permetex black silicone. I hate using this stuff except where necessary because of the bear of removing pans, valve covers etc.

Nevertheless for now, no leaks. I do agree that my Mopar Performance valve covers are likely a culprit here, however also believe that Edelbrock should look at their valve gasket ‘ridge’. It maybe adequate for the front of the head for sealing,,,,but because of a greater tendency to ‘pool’ at the rear the ‘ridge’ needs a bit of refinement. Yes I do now understand that heads are switchable from side to side,,,so Edelbrock should refine both ends. Photos of gasket imprints show very well how narrow they are where as the ‘ridge’ curves upward and this is pooling caused leaks in my case occur.

On more than one set of cast aluminum covers I had to mill the sealing surface. I don't see this as an issue in your case, but in one case I had to take 0.080" off the boss where the bolt goes through because it was hitting the head there and would never properly compress the sealing surface. I found this by putting a piece of paper between the gasket and head and it would slip right out.

I have had the best luck milling the valve cover sealing surfaces flat and gluing a rubber gasket to the cover. Degrease the head sealing surface and install. Usually have zero leaks with this approach.

I realize this is just stating the obvious........ but........ there are thousands of these heads in service....... for well over a decade...... where the owners are enjoying leak free operation.

As opposed to something like a MP 518-M MW head...... where I’ve seen the valve cover rail vary by over .125” in height from one end of the head to about the mid-way point....... then back down again to the other end.

Have fun trying to get that to seal.

Try putting the Permatex on the gasket first by rubbing it in with your fingers .Don't use a lot just enough to make the gasket tacky. Works great for my M/T cast aluminum covers. Studs in the heads work best, 3 pacs for a sbc should give you enough and their cheaper. Then let it set set up for a few hours.

Since earlier post where I slathered a bit of black Permatex on back few inches of head rail head rail, between Superperformance gasket and head,,,leaks on both heads appear gone.

Now I can start removing baked on engine oil of ceramic coating of TTI header tubes under the car. Not as bad as when with rear main seal issues, but still a time consuming cooly labor job. What I found worked best was a toothbrush like brass brush using Mother’s metal polish. Tried several other well known brands,,,but this was the quickest. Header ceramic coating did not appear damaged when completed.

I had thought on Easy Off Oven cleaner. Has anyone tried this. In ovens you are to crank up the oven to hot to get it to work. Has anyone tried this?

Incidentally for you Calyfornua SF Bay Area Members. Goodguy’s June event is coming soon to Pleasanton June 1 and 2. Goodguys has given us one of their 3 main buildings to have 25 very unique and high quality early Mopar muscle cars that we have invited as an inside Mopar only show within their event. Chevys and Fords normally dominate these events,,,a couple of us decided it was Mopar time.

Any of you attending, stop by for a look-see.

https://www.good-guys.com/sgt

Easyoff worked great for me. Let it soak of a while, no heat. I used the ragmans metal polish, pipes looked like new.

I had small leaks when I first installed my heads, I later switched to Superformance gaskets and still had some leaking, I then found that the same size bolts I had used for my 906 heads were just a tad too long. I added a second washer to test and the leaks stopped. Bought some new ARP bolts in a size 1/4" shorter and haven't had an issue in 3 years.

There is no gasket better than its installation. First and above all, flat surfaces required, along with cleanliness. Rigid castings are better than stamped steel pieces. Then, proper torque... and never over-torque, especially with rubber type gaskets as rubber does not compress.. it distorts... too much squeeze and it splits. Cork-rubber and fiber type gaskets will compress. Also, never apply or spread RTV silicone all across a rubber gasket... it will act as a lubricant and welcome the gasket to split or slide out of position; rubber gaskets always best installed DRY.

Read the instructions that should (hopefully) be included within manufacturers gasket sets.

I'm not sure what the difference is between the 1612 gasket and the VS50145R? i've had good luck with the VS50145R on the edelbrock heads, they are both listed as rubber coated fiber. im also a big fan of ARP valve cover studs and their 12 point nuts. i lay them on the head dry letting the studs hold the gasket in place, then i set the cover on and run my fingers around the outer edge of the cover to tuck the gasket into the lip on the cover then i snug the nuts down a little at a time starting with the bottom. like fast says, its a 1 time use with the gaskets, and sometimes you really have to pop the cover to get it to break free when you are removing it but the dont leak this way. i change the oil and check the lash every fall so its a yearly gasket replacement. i do this on both of the cars we have with edelbrock heads. i tried the cometic rubber gaskets and they leaked really bad with these covers. i like the look of the mp cast covers but they really are a crappy piece for what they cost.

Felp-Performance #1612 gasket and the Fel-Pro VS50145R?... exact same gasket.. different packaging. These hi-temp gaskets are rubber-coated fiber and designed for extreme hi-temp OE applications where the cast iron manifolds rise up and very close to the valve covers... intended for ... and tested on emergency/police/fire/ambulances, city taxi-cabs, trucks, heavy-duty industrial vehicles, etc. These are best hi-temp gaskets on the market... period... and intended for longevity. Just remember.. flatness and proper clamp load! They are not as compressible or forgiving to distortion as cork-rubber... also available for Mopar small-block LA covers.

I would put the valve cover on a piece of glass and look at how it sits...that is what I do with it to start, that will tell you if it is flat and how the sealing surfaces look. I would start there, if it is in question, use some aluminum oxide paper to sand it down flat...using the glass to hold it flat.

Bit the bullet and purchased a replacement set of Mopar Performance valve covers,,,I prefer the look.

Also a pair of Felpro 1612 gaskets, as they appear a crowd favorite on the forum at a very reasonable cost compared to some others. I have tried more expensive gaskets from 5 different vendors to not much success.

Also purchased silicone black in the can that lays a bead by merely pushing on the tip of the can, similar to using a spray paint. Really impressed at how much simpler and more accurate verses out of a tube. Summit sells their brand name version that appears same as Permatex at about 1/2 the cost.

https://www.autozone.com/sealants-g...que-rtv-silicone-gasket-maker/388828_0_0

Just installed valve covers this morning,,,will let sit until tomorrow to allow limited areas where I used silicone,,,only at bottom rear of prior covers where I was experiencing leak issues. Hopefully new covers and gaskets, all will be well.

Installed replacement Moparts aluminum valve covers and using Felpro 1612 gaskets as suggested by a member, and a slight amount of permatex black Summit sealer only on rear half of valve cover side of gasket from pressurized container,,,all is well. I have always used 40 pound fish line threaded thru boot holes to hold gaskets in position when mounting. Clean up of old gasket sealer has never been a something I enjoy.

2 weeks driving later, including trip to Goodguys June event for indoor Mopar show, not a drop of oil on the floor upon leaving event.

This after numerous attempts over the years, using gaskets,,,some very high priced,,,from a variety of manufacturers with no complete success. Some reason undetermined, the original Moparts valve covers in spite of multiple attempts just would not seal totally.

ARP studs that I ordered from Summit along with other parts were and still are back ordered. Bolts after a couple additional 40 inch pound torque downs as per Cal’s recommendation are doing fine.

Thanks to all of you who chimed in.

Recently just had to deal with this. I noticed the lip on the covers interfered with Felpro 1612 gaskets ever so slightly. It was enough to off-center the bottom bolt holes on the sides and sometimes it would pop out and not sit flat.. Ground off the lip on both sides in the problem areas and used Hylomar per the recommendation from Mancini and it sealed right up.