Ok, I have a big block engine (396) from a 1969 Chevelle in my '67 Camaro. I noticed that the valve cover was leaking on the passenger side, so I decided to replace the seals. When they were removed, I noticed two large holes on the heads themselves. The holes are pretty jagged, like they were eroded open or something busted through them. In either case, it doesn't look normal, but is it something I should be concerned about?

I searched google for chevy big block heads and came across someone selling heads that had the exact same eroded holes that my head had. Its the bottom pan, on the top left and also right next to the "hi-perf" text.

 

wow, here's another Chevy big block with the same hole. I can't imagine that those holes were there when the engine was manufactured?

 

Those are oil return passages to the lifter valley. Normal in a BBC. Not eroded, just as cast. I usually clean them up with a die grinder when I rebuild heads, so the oil flows easily back into the engine, but they work fine left as is too.

 

kk... I'd just think the cut lines would be smoother. It looked as if something busted through the pan. Thanks.

 

On most aftermarket heads these holes will be small and round, but Chevy didn't do that. I'd guess it was to save a little metal in an area that didn't need it for strength or any other reason.