Yeah, you're totally right siteunseen... I just don't want to tarnish the character of the car. Although that sounds ridiculous now that I'm typing it out, and considering I'd want to put aftermarket rims on it anyway.

By the way, there are several different part numbers flat top carburetors for the North American market. Some were used on the 240Z, and the others were on the 260Z. I cannot attest to the differences between the part numbers.

I suspect the different part numbers are because the early 73 cars used a slightly different design than by the time they got to the end of the 260 run. But with all the problems they had with the earliest designs (as discussed in that fuel system modification document) I believe dealers replaced a lot of them with the same design that are on the 260's.

Interesting. I also just saw mentioned in another thread on this site that some dealers would even swap the carbs themselves from flat to round top due to the issues the flats were causing.

I wasn't there to confirm the situation, but I have heard the same. I guess if you went back to the dealer a couple times and made a scene, I've heard some would put round tops on it to appease an unhappy customer.

All that said, a true stock 73 should have flat tops, as should a 74. I can deal with an early 73 having a set of later design flat tops (since that update is documented in Nissan's literature), but I would start subtracting points for any round top on a 73 or 74 in a stock class.

Flat Is Phat!!  (I didn't make it up... I'm just promoting it.) 

From the parts book


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 That confirms it. I'm assuming the next gen. flat top started in July

On ‎5‎-‎12‎-‎2017 at 1:48 AM, Mark Maras said:

According to ZTherapy's Spotters Guide, the flat tops started in June 1972 and lasted through the 260. 1974.

And in europe they had the flattops till 1978, i even know a late sold 78 that is registered in the Netherlands as a 1979 model and has those flattops..  When the engine is cold they are very crappy but after a warm up the engine runs better.. but still a set of roundtops could make it run a lot better.. cold and warm..