I am looking at needing to cut and add a sweep to some underground conduit, as the arrangement of the service has changed.

This was installed 40-50 years ago. The crud is down 5' in a hole and is tough to get at.

What sucks: it looks like 2 1/2" abs. It certainly is All Black Stuff. But no such size exists.

It really is down pretty far. Any deeper and I could drop a casket in there. So I am having difficulty working out exactly what it is.

So I wonder, is it in any practical way possible to join ABS to grey pvc? That I can get in 2 1/2", including a sweep.

I wonder if I need to just use a rubber coupling?

Or have I got it all wrong, and the stuff is actually 2"? I would not put it past the local utility...