Installation Of Round Tops In A 73 240

[beandip]

the difference is that the linkage rod that connects the two carberators is too short. If you cannot come up with one from a bone yard or someone on this site get back to me I know a guy that might have one , it's just that he is hard to contact , but let me know . Gary:classic: After thought, I wouldent remove the '73 manifold if were me . There is nothing to gain by making the change. Just strip off all the unneeded stuff . You need to use the spacers from the round tops that are thicker that your old ones. Also the earlier air cleaner box. You can plug the large inlet from the air pump like was said before all that is needed is the vacume line to the brake booster and the carb vacume to the advance on the dist. :classic:

[Bambikiller240]

Try Danny's Datsuns

or

Eric at ZParts

[Driftin Jon]

I did the conversion this summer. I got the carbs only and put them on the old manifold. Block off all water passages. Surprisingly, all water passages I found to be NPT (national pipe thread) fittings. Blocked everything on the manifold except PCV valve hose and vaccum to the brake booster. You will need a new linkage that you can get from Z Therapy for something like $15.

Fuel mileage went from about 14 mpg to what I think is a very credible 19 mpg around town and 30-31 on the highway. I was pretty shocked by these numbers, but they're very consistent.

The other thing I've found to be surprising having read other posts is that I've never had a vapor lock issue. It's not unusual for it to be 100-105*F here and the car has performed flawlessly this Summer. I don't have any insulation whatsoever on the fuel lines either.

You'll like the improved driveability after changing over to the round tops.

[Go240Zags]

Is the manifold from the 1973 240Z the same as the one in the 260Z w/ the flattop carbs? If so, won't he need to use the thinner spacers because the studs on the 260Z manifold are shorter, or do like I'm doing and swap the studs from the early 240Z manifold? I tried my early carbs with the shorter studs, but just barely got the nuts threaded on. Bought some of the thinner spacers, but decided to just swap studs and use my old thicker spacers. I'll post a couple pics with the carbs mounted on the N36 Intake from a 260Z to show how the nuts barely thread on to the shorter studs. Anyway, if the 73 manifold has the longer studs my question is moot. Gary

[remedy]

My car currently has a single downdraft carb on it off a Cedric or something similar. I have two sets of SU's and want to fit one of them. One of which I think is a set of 'round tops'. Which one of these should I use:

[Bambikiller240]

I'd use these : http://www.classiczcars.com/forums/attachment.php?attachmentid=7806

The others are BOAT ANCHORS

[remedy]

what service! thanks for that

[clutchdust]

remedy, i don't speak from any position of authority on this issue but if you go to the ztherapy website and look up their carb information they say that first set (w/o air filters) are only good for wheel blocks. you should probably ask bruce. i think the site is www.ztherapy.com. but if that doesn't get you there, you should be able to find it through a search.