Don't know, but is this an original or aftermarket fuel cap ?

Not original, the original has a handle on the top, or all the ones I've seen do.

It doesn't look like the ones I had. There's only one part number listed in the online parts manual. It's 17251-N4501, and it's still available from Nissan.

OK...

I did found a picture of one on google, makes me wonder if it might be an original one ?

http://www.whiteheadperformance.com/wp-content/uploads/2013/03/1971-Datsun-240Z-Gas-Cap.jpg

This one ?

http://www.whiteheadperformance.com/wp-content/uploads/2013/02/Datsun-240Z-OEM-Gas-Cap.jpg

Bart it is original . Yours is an early cap with no handle , you even have the rubber drip strip still . Your chain is missing .

The last pic is of the mid 71 and up replacement .

Edited October 29, 201311 yr by Unkle

Mine looks like above post with a chain attached.

Bart it is original . Yours is an early cap with no handle , you even have the rubber drip strip still .

The last pic is of the mid 71 and up replacement .

The interesting thing is that they used the same part number. I was looking for a part number change to indicate Nissan moving away from that style.

Mine looks like above post with a chain attached.

Same as mine....4/71 build date.

Definitely an oldie AND goodie, same as the one on my car and I know it is original.

Get a yellow zinc replate job and it will really look sharp.

Re. the comment on the missing chain, on this model the chain is inside the filler tube when the cap is in place.

Edited October 29, 201311 yr by jfa.series1

Same as mine....4/71 build date.

ahh... then I might have one of the last ones of the early type cap ? since mine is 5/71

Definitely an oldie AND goodie, same as the one on my car and I know it is original.

Get a yellow zinc replate job and it will really look sharp.

Re. the comment on the missing chain, on this model the chain is inside the filler tube when the cap is in place.

Thanks on the chain comment... I can see that is missing.

I did give the cap a quick sandblast today, and painted it grey, looks okay for me.