I prefer to have negative pressure in the engine. So I've made a dipstick which seals with 2 o-rings (fits in the stock dipstick tube) and I use an oil filler cap with a center hole into which a fitting with a reduced hole goes. When I have it choked to the point of what I think is the right engine negative pressure (positive pressure encourages oil leaks) then it goes to a hose which in turn is filtered. On the valve cover, I have made wide spreader bars which keep that sucker pressed down tight out of aluminum...as I recall it was 3/16" thick. You can see them here.
https://beta.photobucket.com/u/JonGoodman/p/9ce484b5-5a62-475f-886a-8b51a08ceca0

There are 2 of these on each side of the valve cover reaching end to end and meeting in the center.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end