When I bought the boat, there was oil on the valve covers leaking from the breathers....and the gaskets .... I pulled the covers and they had been attacked with a drill at some point to attach 'tall ' ' breathers that had nothing inside them.....hard  to explain, I'll post a photo later.... The valve covers were ruined.

ANYWAY...I bought some aluminum welded covers and the first set was not even close to being right... They were not square...didn't even
Bother putting em on.   Really crappy welds.....I returned em. Got another set..... Holes in the welds....bad craftsmanship ... Returned em.... Got a third set..... Better.....but  They leaked too.... Changed gaskets 3 times ... STILL leaking...... Put the puke tank on, and it did help..... But them sons a bitches are dribbling ......and I'm running out of degreaser and rags.

 So I bought a set of steel covers and I'm waiting for them arrive. 

Gaskets .......

Cork or rubber??   Or rubber with the steel Inserts?   

Running some casted aluminum covers on my boat ( ford racing ) pretty nice, they have tall breather with the sponge foam piece and about half inch hole also. No leaking, no PCV, no puke tank, running fel pro marine cork gaskets. Been good

I have a buddy who had problems with the fabricated style covers also. Holes didnt line up at all.... Seems to be somewhat common with these. They look really good when they work properly ! I think he had bought the pro comp covers....

I have a set of those hand made valve covers and also had trouble getting them to seal. I ended up doing gasket maker, then a cork gasket, then gasket maker. They don't seem to be leaking anymore. Also found a pin hole in one of my covers that was leaking oil. A little squirt of gasket maker fixed that too.

Sounds like a joke... Not trying to be negative, but man, at some point you gotta say F-it ! Haha good luck guys 👍

After fooling around with the current set I noticed they were not seating completely due to the bolt holes are not even...... 2 out of the 7 bolts will
NOT seat..... I put extra washers in an attempt to make the bolts tighten but no bueno...... I even took a tap
And chased the holes on the heads to make sure they were clean.... And allowing  the bolts to go all the way in but NADA.....   It's not a lot..... but it aggravates me to no end......and it makes a mess of the engine compartment .....

We use the fel-pro blue stripe gaskets on all our dragster stuff because I lash the valves every other pass, they work bitchin and last 3 years or so.. Also, try studs if the bolts bottom out..

I'm 90 miles from home; out on the lake on vacation......these &)(£<%# aluminum valve covers are designed to leak I'm positive.....

The steel ones I bought came in, so I got up early this morning.....and drove the 90 miles back home, bought new gaskets;drove back to the lake....installed and oh yessssss....... they DO NOT LEAK!!!

The expensive,hand welded, look really nice,but leak like a sieve valve covers are headed for the scrap pile.....

I'm guessing the alum ones are warped. Sometimes when welding things get out of whack.

Any chance they are procomps?

Not sure , I'd have to look at the receipt .....

They are not warped, they are 'square' .... But the bolt holes are out of line and different heights...  bad execution by the welder. Or.... The welder was stoned ...... Or was hung over or something.

The 'wells' where the bolts dropped thru the top of the covers are off.  The shoulder of the bolts would not seat on 4 of the 14 bolts... And there were 2 spots I found where the welder burned thru and left voids....

These cheapo steel covers I bought work....   

Go figure...

... Burned through nearly 100 gallons of fuel the past 4 days..... Valve covers never leaked......