It's not just Edelbrock heads you can restrict the
oil to, but all FEs, for the reasons Clois mentioned. It's best to do this before you install your heads, so you can remove any chips:
Tap the
oil hole in the heads (under the 2nd rocker arm?) from the top 5/16 - 18. Get a couple 5/16 - 18 X 1/4 long socket head set screws, and drill a 3/32" hole in the center. Screw set screws into heads, making sure the rocker arm stand & bolt clear.
An option is to get a couple pieces of round stock (1/4" dia.? X 1/4" long), drill a 3/32" hole in the center, and slip or tap them into the oiling hole in the heads. I'm sorry, you'll have to measure the current hole size yourself. I can't remember.
Good Luck,
Dan