Caterpillar 3406B serial number lookup?

I am about 48 hours away from buying a used (85-86) 3406B Cat engine, one that's out of an old Autocar and the guy that's selling it to me was going to use it for a different application in a soil aerating machine. Turned out he didn't use it because of different bell housing and other issues that wouldn't work for him, so he's listed it for sale. I came along and lo & behold, I needed one anyway.

It's tough going by what somebody selling something is telling you. He claims it is a...

Caterpillar 3406B serial number lookup?

Caterpillar 3406B serial number lookup?