When I pulled the rear casting plug yesterday on a 261 that I am rebuilding, I discovered something strange...two plugs in the same hole!
The rear plug is the one behind the bellhousing that fits in the 2" hole with the lip that takes a concave plug that gets tapped flat. The inner plug was steel and the outer plug was brass. I thought it looked a little odd that the brass plug was almost flush with the edge of the block, but didn't think much of it until I took off the brass one to find a steel one underneath it. The two plugs fit fine.
Could be that there was a leak and someone took an easy (or brilliant) approach to fixing it by adding a second plug? Or was this done as a belt and suspenders approach intentionally when the engine was put together to keep the plug from ever leaking because it is not easy to get to when the bellhousing is in place? Even with the forethought of using two different metals in case one gave out?
Thoughts? I've never seen it done before, but now I'm thinking that I should do the same thing when I put it back together since two plugs fit just fine.
Also, anyone know where to find 2" brass concave plugs? The 1 5/8" brass cup style plugs for the sides of the block are easy to find, but I have only been able to find steel 2" concave plugs. I'd prefer to use brass if I can find one...or two!
Opinions welcome...thanks,
Matt
