Find Edelbrock Exhaust Crossover Plugs 2733 and get Free Shipping on Orders Over $99 at Summit Racing! Edelbrock exhaust crossover plugs are designed mainly for use in marine or off-road applications. They are made of cast iron and install into the exhaust crossover without any modifications...
The iron plugs need ground to hand fit each of them. Some have had them "rattle."
I've heard of making "thin" stainless steel plates. Good luck with that. The best is to fill them with Mondello's "famous" zinc-alloy or melt a couple old pistons but do it before the valve job. I have 3 sets that are filled. My C's were done by Shargo Racing, hmmm, 25 years ago. Big valves, ported and filled with zinc-alloy, exhaust divider welded and oil return lines added. $$$ car ran 10:90 with heavy Speed-Pros.
Second set are #6s, 2.05" intake valved, ported, filled intake crossover plus welded exhaust divider. They were done by G&G Engineering in Cleveland. G&G were big time Oldsmobile racers that were always at the Oldsmobile meet @Norwalk. $$$
I have set of #6's partially done, crossover filled, new big valve seats, ported, exhaust divider welded. Empty no valves or springs.
The C's were easy to "dig" out, so I took some pictures. Zinc-alloy.