LA series cast aluminum valve cover leaks

Yeah, I know....when these engines are built back to stock, everything fits and works as intended. Stamped steel valve covers, Iron intake, etc.
When we deviate from stock, things start to get messy.
Take for example, the popular cast aluminum valve covers that many of us like to use.
Holley, M/T, Mopar Performance and others.
Why is it that every one of them had the same exact problem? The gasket rail at the top hits the intake. You have to grind away part of the gasket rail to get enough clearance to allow the valve cover to sit down properly.
This is some piss poor quality control. What was the point of the intake runners having those nubs or runners hanging into the space occupied by the valve covers anyway?
I did a search here and found absolutely nothing about this.

Well then it's been that way for many years then. Had that problem with M/T's many many years ago.
1 fix was to use thicker gaskets.
Just part of working on these older cars.
Can't expect 0% problems, now can we?

I have used the M/T covers on both small and big blocks(with aftermarket intakes) and don't recall having this issue. But then it was many years ago. I had more problems with the breathers.

Had the same problem wit Mopar Performance ones. Always leaked. To be honest, sometimes there can be other issues like intake clearances with aftermarket ones. Gaskets for those can be hit-n-miss to. When I put some one my next engine, I'll probably make my own cork gaskets and use some rtv and machine the lip on the covers so I won't have the same issues again.

A departed good friend once said they should just make one set of instructions for ALL aftermarket parts.
1. Take off the old sh-t
2. Bolt on the new sh-it
3. Turn the key and go

Over the last 50 or so years I have found 4 exceptions that come to mind

1. Schumacher conversion mounts
2. Trim parts
3. RMS suspension
4. Legendary interiors

if everything fit and worked as one would expect it to, one would not learn "new words".

^^^ Exactly ! How can I expand my range of profanity without hot-rodding something ?

The MP VC deal, their SB stroker pistons, etc ad nauseum were things I've posted or referenced here long ago.
Countless others of course have had similar experiences.
MP lost me as a customer somewhere around 2002.

My machinist has a saying: "If it comes out of a box, it's fk'd up. If it wasn't, I wouldn't need all this expensive machinery to make it fit".

Kevin

Funny part is I have Indy heads, aftermarket cast valve covers, aftermarket intake and they all play nice together with Superformance gaskets

Gus

I know that it is a small issue in the grand scheme of things.
It just seems like a strange thing to have a problem with. There are things where if everyone was doing their job, the conflicts wouldn't exist.
I could see if the heads were extensively milled, the valve cover gasket rail is lower and closer to the intake. I've seen this problem on old, unrebuilt engines. Even small port 273 and 318 intakes extend into the gasket surface. Why???

Because the factory didn't care about this as it was a non-issue for them and the aftermarket doesn't care because it's a YP not an MP (Your Problem, not My Problem).

Probably one factory casting these things, just change the name on top as needed, and they do not care.

Several decades ago when I was building one of my small block W5 race headed engines, I bought an MP 90° oil filter adapter. I pulled it out of the box at the parts counter and studied it for 5 minutes. The parts manager finally asked me what I was looking for. I told him I'm trying to determine what I will have to grind, file, machine or otherwise modify in order to get it to fit and work.

I think my old buddy was probably a lot more accurate with his thoughts on almost every aftermarket parts. His went like this:
1) Take the old stuff off, save it, you might have to put it back on.
2) Test fit and modify the new stuff to fit like it was suppose to fit.
3) After modification, bolt it on, and hope it works.
4) Clean the mess up. Go drive it. Then keep the mess cleaned up.
5) If it doesn't work, you can put the old stuff back on, and sell the fancy junk at a swap meet!

#1 wasn't gonna happen especially with a case of Bud light
#2 Test fit, Now we're rocking, get me another Beer
#3 Get me another beer
#4 After 6 beers modifications looking good, Get me another beer
#5 Bolt it on and admire your CRAFTMANSHIP AND INGENUITY while having another beer
#6 Send the wife for more beer
#7 If it doesn't work right, have another beer and force it
#8 Have 2 more beers while digging through the trash and empty beer cans looking for the original.
#9 HMM Looks better now, have another beer and throw the original in the swap meet pile.
#10 have more beers while cleaning up the carnage
#11 next morning wonder who screwed your car up
BTW I've been dry for 5 years

Might be ancient history, but in the late 80's Micky Thompson and Holley valve covers were both manufactured by Winters Casting Foundry in Canton Ohio. Probably come floating in on a boat from China by now. Winters made a lot of other castings, not just automotive items. Heard they also made castings for washing machines too.

Depends on the manifold too. Some hit the covers and some don't.

Seems to me the aftermarket used a 318 engine to mock up their tooling, since there were a lot more 318's than340's. The smaller 318 runners didn't hit the valve covers where the bigger 340 runners would. Almost every aftermarket valve cover bolted onto a 340 needs the lip on the cover ground down.

I'd buy that theory if the same issue didn't apply to the B/RB covers as well. Cracked a brand new set of MP cast valve covers tightening them down on a 413 back int he 80's. That's how I learned about it.

gasket got thinner over the yrs is my opinion. less cork = more $

fel-pro high performance gaskets or superformance gasket are the best I have used on a regular basis.

when I double up cheap paper intake gaskets they seal and don't suck oil on bottom of the intake runner.

when I run my M/T VC I use the thickest high performance cork gasket - felpro 3/8" thick- I use the Indianhead gasket shellac to glue gasket to VC on the bench to get it perfect flat alinement on VC.

add a very thin coat of Permatex copper silly cone on head side of VC gasket or spray with copper spray gasket tack install and finger tight the bolts-let sit over night and then snug them 3/4 turn with a 1/4" ratchet/socket by hand.

they never leak.

do my stock tins same way.

in my opinion the VC bolts are always way over torqued and crush gasket surface. but when glued/sealed/cured and lightly torqued down the stay leak free a long time. don't forget to hammer the tins around the holes and make sure rails are still flat.

use cork and don't crush the gasket surface, shellac is a [censored] to clean but seals well for a very long time. I use it in most leaky gasket problems like VC- oil pans-t stats ect.

Ahhhh….. that first set of aftermarket heads I bought! Raised wide flat valve cover rail! At last!!! No more leaks!! …..to bad the distributer wouldn’t fit! RB Stage VI survivor

If it were easy, then anyone could do it. That wouldn't be good.

Oh, I heard a lot of angry stores about that problem back in the day. Man, I heard one guy was so mad, he tried fringing the clearance by hand and ended up ruining the head. 😂