That's the remains of air injection tubes- - - -one of the first attempts at emission controls. Those engines had a belt-driven air pump and steel tubes going to each of those holes, with a one-way check valve to prevent exhaust gas from getting to the air pump. The permanent fix is to remove those tubes, by whatever means possible, chase out the threads with a 1/4" pipe tap, and screw pipe plugs into the holes. If you want a really slick-looking repair, get some of the pipe plugs with an Allen-head socket in them instead of the square head a regular pipe plug has.
Jerry
Last edited by Hotrod Lincoln; 05/15/2010 5:09 AM.
