The solid lifter version of the FE is known for pumping a LOT of oil up into the cylinder heads. It is one reason the rocker assembly seems to last so long, but there are many who think it is too much oil. Oil is used for lubrication and cooling. The problem is made MUCH worse if the wrong oil pump is installed, because there is NO NEED for a high volume or high pressure pump, because the stock Melling will do just fine. Perhaps if the system is worn, maybe you are pumping more oil up there than intended?
In high performance applications guys have found the oil delivery and rocker arm feed system will flood the valve covers at sustained high rpm running because the drain back system is "limited", and this not only floods valve seals on the lower end of the motor if it is tilted like a marine installation, it can also starve the main oil sump and potentially cause damage. In order to compensate for this they install a .090 or .070 Holly jet (restrictor) in the hole under the rocker arm that has the oil feed to the upper system. All that oil comes through that little hole
NOW IMPORTANT.........BE SURE THE ROCKER THAT GOES OVER THIS HOLE has a receiving hole facing down, and not up !!!!! They can be installed backwards. Also the bolts on the rockers REQUIRE flat washers, and if you just use lock washers you will have a flood up top
Just thought I would toss that into this thread.
If too much oil is getting topsides because the rocker assembly is worn, then I would not recommend reducing oil flow. Just curious about the entire oil flow conversation to this point, and a question: "which plugs are fouled"?? Just at random or perhaps the ones at the aft side of the cylinder heads, would tellme something.
Check the drain back holes they are known for being blocked if too much sealant is used for an intake gasket installation........remove the valve cover and take a look down in there. If so, this just puts too much oil up around the top of the seals, and of course if you flood them then more oil will get in.
I have some good photos of the seals. If you are careful to not let a valve drop, you can change them in the boat without pulling the heads. Certainly a LOT of work, but can be done. If it were me, I would rotate the motor each time I got to a cylinder to be sure the piston was up there as assurance to dropping a valve
Here is a note from Randy, from our archives
The oiling issue in the CC427 or any FE is real, I installed restrictors under the rocker
shafts of my newly tweaked 427s (now 468s) to reduce the amount of oil going to the top over
3,000 RPM. If you don't, the oil level gets scarey low in the pan because all of it is up in
the top of the motor. The lower viscosity the oil, the worse the condition gets. I was watching
for it with a modified set of valve covers. The rockers still get way more than enough oil with
the 0.090" restrictors installed. Again, like you said, sustained RPM in boats versus cyclic in
cars is a huge difference. The installed angle of the engine also changes the oil level indication
on the dipstick, I am running one quart over the full line, which is 8 quarts in the pan. Any less
oil in the pan compounds the issue of too much oil on top and can cause cavitation of the oil pump.
Also.........from our archives which are available free to anyone for personal use.....is a photo of the hole below only one rocker arm that feeds the entire upper end, one per bank....
Here is a solution.........should the issue actually apply to your motor and boating style.
I have this issue on the 427 Lancer for sure.......... A neat little Holly jet fits right in there.
Here are a couple photos of my valve seals
Plug type, brand, style, gap, and maybe even the wire to that plug, could also be a contributing factor. In addition, I would always check the PCV system as a side note, just because if you are in there, just do it.
Lastly, one more thing about the change out of valve springs and seals while in the boat. Some guys use a compressor, remove the plug, install a threaded fitting with the air hose, crank up enough pressure to hold things tight but beware, this could easily rotate the motor so keep fingers and other things clear.
Good luck with it, I'm sure there are some other guys with some tips, so let em come on!
I think I would try chaning to a different heat range plug first, because it's easiest