Can you help id this slant six..!?

I have a lead on a good 72 motor. I’ll let you know how it works out or if I’ll take you up on the offer of the 68.

Let me know when you want to come out and pick up the 66.
OK , I'll talk with you when I return from the motorcycle trip I have been on since last Thursday . That should be in a couple days on Friday. Thanks