[dataway]

I've got a set of the 5/16 Edelbrocks right now. They might do the trick.

[gtofreek]

And Tin Indian Performance sells a thick rubber gasket, I believe is 3/8" thick. Used them a few times to get clearance for stock valve covers.

[Old Goat Racer]

1/4, 1/2, 3/4, full turn or even 2 full turns ? Pick one .
That's what I had to do just last week. Because I had no idea what kind of lifters were in the 400 motor. I didn't build it.
Took it apart, checked brgs. etc. Installed all new gaskets including a GM NOS rope rear main seal.
Set the lifters at 3/4 turn like always, dropped in the dizzy, through the keys in the front seat and it fired right up and idled.
3/4 turn, been doing it for 50 + years.

[Old Goat Racer]

Oil drippers. How many years did Pontiac use them before they threw them away ?

[Formulas]

At some point pontiac went to a integral valve cover dripper systen that was spot welded to the top of the covers on the inside. .. I have a set of those

[Old Goat Racer]

Originally Posted by Formulas

At some point pontiac went to a integral valve cover dripper systen that was spot welded to the top of the covers on the inside. .. I have a set of those

Well aware of that. I have several sets. I was referring to the bolt to the head studs.
Why did Pontiac throw them away, NOT use anything and then bring it back a different way.
Mickey Thompson covers never used that design.
Maybe an engineer could explain ?

[dataway]

I know that my GTO that ran 130,000 miles had them, and the OEM rockers still looked perfectly usable .. until I lost them. I have considerable faith in engineers when they ADD something, maybe not so much when they take something away. Bean counters will gladly agree to the take away, the engineer probably has to SELL the add-on. Just makes sense to me, take the oil shooting out of the pushrod and send it to the rocker fulcrum. Very rarely does too much oil cause a problem compared to too little oil.

[Formulajones]

A lot of engines produced don't use them. They aren't a bad thing to have, just that they usually get in the way on a performance application. Most all the aftermarket covers sold don't have any type of dripper, and any performance build from reputable shops don't incorporate this stuff and have no ill affects.

I have engines with and without them and there is no difference in longevity or any wear issues of any kind on either one.
The original covers on my 69Z never came with drippers and are actually hard to find and coveted by the die hard restorers. GM didn't start doing that until 1970 and now all the reproduction Z and Vette covers have drippers.
I removed the drippers on my chevelle back in the 80's when I switched over to Crower full roller rockers. Those rockers are still in service today with no issues, and no drippers. Street driven regularly and raced.
I removed the drippers on my firebird more than 20 years ago, still running the same rockers on that engine. Driven and raced even more than the chevelle, never any issue with valve train.

If you've ever primed an engine with the valve covers off (I do on all builds) you would see how flooded the rockers get with oil. There is a ton of oil pumped up there to the point I stop the drill and give oil a chance to drain out of the heads, because it will completely fill the cylinder head and run down the side of the engine. Some engine builders even run oil restrictors to limit oil up there in certain applications.

Bottom line, oil drippers are not completely necessary, thousands of engines out there without them. But at the same time, if one wants to use them, there isn't a drawback other than they sometimes take up too much room.