This is a duplicate posting. Sorry for this. I didn't think the title of the 1st posting reflected the subject properly, and I know there has been some recent interest in this topic. I tried to edit the original posting, but the system won't let you modify a title, only the content.....
I just finished what I consider two critical modifications to my new Edelbrock Performer RPM heads which I am installing on my 428 CJ block. The purpose is to maximize the oiling performance, a vital key to making these engines survive. Note I chose the Edlebrock 60079 heads designed for the 427, which will bolt right on to the 428. I chose them for the single exhaust manifold bolts, and the 76 cc chambers which were more suitable for my 11:1 pop up pistons.
Step one was to modify the
oil drain holes to prevent
oil from accumulating in the corners, and drain quicker.
First, the holes were ground out larger, and tapered using a Dremel grinder. There's lots of meat here, so don't worry about cutting into a water gallery or anything. This mod can be done without removing the valve and springs, but be careful not to accidentally nick the valve spring with the grinder...
Next, the metal was polished smooth....
The resulting hole eliminates the sharp edges and provides a more funnel-like drain shape...
Next step was to restrict the
oil flow to the rockers. This oil is fed from the block via a passage beside the middle rocker stud. Step 1 for this mod is to tap the existing hole, which , co-incidentally is the perfect size for a 12-24 tap....
Step 2 is to instal a special restricter plug - in this case an .090" hole is drilled through the center of the plug so that some oil gets through, but not the full gushing amount you would see from an unrestricted hole... this would lower pressure, and the oil can be used more effectively elsewhere (like the bottom end). The threads are tapped to a depth so the installed plug bottoms out and sits about 1/8" below the top surface. These plugs are available from Precision Oil Pumps
www.precisionoilpumps.com, tel 559-645-1951, Madera CA...
Finally, the plug is screwed in and, voila!
Finally, get rid of all the shavings. All I did was take the heads outside, wash them off with the garden hose and a nozzle (they can't rust, and water will not wash away the factory installed grease on the valve guides), blow them off, and allow to air dry. Now the heads are ready to be bolted on! Of course, this is what I did...I doubt Edelbrock would sanction this or claim it is necessary. You need to decide for yourself if this is a good mod for you... As well, there are a number of well known "bottom end" mods that should also be done to the block, but that is an whole separate topic in itself, and is well documented in the various FE books. These upper end mods are only a part of the solution...
