After receiving a box of parts back from the vapor honer, I noticed that the two lower thermostat housings I had are different. One came from a 72, the other I am not sure.

I believe the one on the left is part number 11061-P0300, which the microfiche indicates was used on 1973's.

So I suspect the one on the right, having lighter-duty top and head flanges, is 11061-E3000 and is for 70-72. Can anyone confirm?

What's on your original early 240Z's?

This pic is from a mid-1970 car. I believe it is original. (I have no reason to believe otherwise):