if you have a head off look at the drain holes close to exhaust side, the oil from drain tubes (via the pushrod hole comes out the same spot. if the lower drain hole is clean same amount of oil goes to oil p drive and timing chain hole .the holes at front of block 1 is lower than the other so some of the drained oil will go to the rear oil pump drive gear
in fact with drain tubes are removed and oil hole blocked less oil spills than when tubes in. this site had a good storey on proper blocking the tubes. run a 5/16 tap down the rocker stand drain hole ,take a 5/16 allen screw and grind a point on lower threaded part. this blocks the oil and positions the stand making it easeyer to install. ps the hole for the drain tube is rich size for 5/16 tap.

unless 1 removes rocker shaft core plugs ,not likly you will clean the sludge out of the shaft as it accumulates preset drain tubes

Meteor, properly installed overflow tubes empty into the rear pushrod hole, not the drain holes for the rocker area.  Pressurizing the rocker shafts increase the amount of oil that must exit the lower oil drain holes.

John - "The Hoosier Hurricane"

rocker shaft cleaning ,must remove core plugs to properly clean sludge. to many on this site worey about oil return,the tubed that bleed off pressure exit into the outer drain holes Exhaust manifold side. these holes easly cleaned with oil hole brush. so when you throw away the bleed tubes and go to pressure lube the oil flow goes threw to the same aria the tubes direct, just be sure to block the holes the tubes wherein.

my full pressure 292 can idle with the covers off and all the leakage goes down the lower drain holes in the heads, also with full lube oil runs down the push rods. with good lifters and cam the pushrods .rotate well. . when i did the engine made sure to use tried umbrella seals for a ford 289. engine never smokes and oil consumption good. . engine in 1949 mercury. i/2 ton

The early ones flowed down the holes in the ends of the heads, they later changed and the tubes were directed down a pushrod hole. I think the holes in the ends couldn't keep up with the flow and what seeps down those holes after the change was adequate enough for lubricating the dist gear and chain.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

Also important to mention about the tubes at the end of the rocker shafts is that the oil that comes from these goes down thru the hole in the head and the front one helps to oil the timing chain and the other to oil the distributor gear. There are mixed opinions about closing these tubes off so as to pressurize the rocker shafts for better oiling of the rocker arms. Some members say to insert a small drill bit in the end of the tube and squeeze the tube around the bit to reduce the flow out of the tube and still have an adequate amount of oil to oil the dist gear and timing chain and a higher amount of oil supplied inside the rocker shafts for oiling the rocker arms. 

Once you have the rocker stands removed, spin the engine over to make sure you have an adequate supply of oil coming from the hole from the center main bearing that will feed the rocker shaft.     Hope this helps 

Bud in Northern Arizona on route 66 in Winslow (standin' on the corner)

If you're American, buy American

631/2 Galaxie 500XL 406   55 T-Bird

At the very least you will need to diassemble and clean out the hollow shafts.Several topics on this if you do a search using "search" at top of page.By the way the oil you are seing on the pushrods originates from an oil squirt holet in the front of the rocker arm.There is also one on the back and these small holes are almost always plugged up too.

  

MAN I LOVE THIS SITE!, You guys ROCK, I am tearing it down to clean and check this out ASAP!

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   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

 Here's a few pics of the passage in the head... the dog leg on the chamber side and the hole under the rocker stand. Oil should flow from the center cam bearing up thru the block (one passage on each side), across the dog leg,up thru the head,thru the rocker stand into the rocker shaft,oiling the rockers ; the excess flows out those tubes to return to the oil pan.    Barry