Does anyone know when in 1974 (what month) that the bumpers changed from the 240z style to the bigger 280z type? I've always heard of early '74 vs. late '74. Now looking at my 260z, which has the earlier 240z style bumpers and turn signals down below, I see the production date in the door jamb shows 8/74, indicating the final month of 1974 production. Can someone shed some light on this?

Actually the late 260Z came out in 9/74 because Nissan was running behind in the development of the 280Z which didn't come out until 12/74.

Ah, so all '74 Zs (early) got the small bumpers and the switch to big bumpers starting in 9/74 then was for the '75 260z (late). I was under the impression that they did the switch earlier. Thank you for clearing that up.

For whatever reason, the 260Z with the large bumpers is still referred to as a 74 even though it came out so late in the year. I've seen them registered as 75 but all the manuals, literature, etc. seem to see them as late 74.