Dumb question probably but why does the duramax not have individual intake runners?

[rickcdewitt]

When i was doing head gaskets and studs i had to stop and wonder why our motors have what is basically a valve cover bolted over the intake ports? I know space is an issue but hell you'd think the intake ports would have a radius on them at least.

Is there some kind of scavenging or other benefit?please school this diesel dummy:binky:.thanks!