wfl_colorado

I am in the process of the same change out and there seems to be a ton of hoses, vacuum lines, etc. It looks like there is another thread from earlier this month talking about the same topic. This seems to be a pretty common swap, but I too have not been able to find much good info on the topic. I got my old flat tops off yesterday and am ready to install the round tops. the biggest issue so far was the antifreeze. Now I will need to add a coolant line to circumvent the carb connections. I think the best way is to view a few photos online. I did not change the manifold or balance tube as they both(72 and 73) had the same markings. I will have to take a look at the air pump connection. Bill

Yea, I think I have seen that silver one you mentioned.

Michael(the owner) had sold it to a guy in France and stored it for him for quite a while. Michael then bought it back and is again trying to sell it. It was sold to the guy in France for 30K. Didn't know it was that well known, but it is a very nice car.

In case someone has some money.... Here is an awesome award winning Z. I actually went and saw this Z over a year ago and couldn't believe my eyes. A very nice car!! Bill http://denver.craigslist.org/car/115450409.html

I talked to Bruce and Pam from Ztherapy and I have an old SU video tape that has explained quite a bit. I think I will try and fix what I have before spending $600 for a new set(althought they look pretty nice). I took a quick look at the throttle shafts and they don't look bad, but I understand the need to see them operate in order to see if there is an issue. They have to be better than the non-working flattops that I have on it right now. I just need to get the new parts and put them on the car, but like Enigma said, it is like 10 below right now and the garage is not the place to be. I have read a bit about the intake manifold as well, but not sure I need or want to swap it out. Steve, I will send you a PM. Bill

I have a 73 240z in which I am trying to swap out the flattops w/ a set of 72 SU's. The weather is a bit cold, so I am dragging my feet since I don't plan to drive the Z in the snow! I have zero experience w/ carbs, but these seem to be fairly simple. I did a basic tear down of the 72 carbs and found a few things.... The tubes in which the needles reside were stuck firmly and would not move freely like they should. I was able to remove them, but ended up pulling one of the nozzle ends off during this process. I guess this needs to be replaced as this is the seat, right? I also removed the float lids and it appears that one of the floats is bent severly and is either melted or damaged under the float arm. Again, I guess this needs to be replaced. I believe these carbs will be fine w/ a new set of nozzles and a new float, but wanted your opinions on whether or not you felt I should replace the needles as well. They look fine, but how can I tell whether or not they need replacing? Also, what does everyone recommend regarding air cleaners? I don't believe my 73 air cleaner will fit the 72 carbs, right? What other options besides K&N? Also, where can I get the hardware to mount the air cleaners, etc? Sorry for all the questions, but this is just the start... Once I get to the actual swap, I will have a whole other list. Tx, Bill

Lance, I am not sure they will work, but I will let you know. Tx, Bill

I am currently trying to swap my flattop carbs for a set of 72 SU's and I failed to realize that the air cleaner setup needed to change. Does anyone have a decent air cleaner box that will work w/ a set of 72 SU's? If so, let me know and we can discuss price. I understand there are other options using K&N etc. Anyone have details that won't drive the cost up too much? Tx, Bill Colorado Springs, CO

Thanks for the info and advice. I will keep you posted of my findings. Bill

I would really like to understand the issue w/ the flattops before I do the conversion. I am going to try a few things first. Like is the rear carb even getting any gas? Secondly, is there something wrong w/ the front carb regarding excessive gas(stuck float, etc)? I think float investigation requires carb removal, correct? I have read something out of the Haynes manual that talks about a float window that can be observed while on the car. Anyone know anything about this? Kenny, does the shop you refer to near Longmont have a website per chance? Bill

Bryan, Do you remember why? Is this the water passage issue or what should I look for? Tx, Bill

Looking at eng pics w/ roundtops they sure look a lot cleaner than w/ flattops. It appears a lot can get stripped off. Are there any basic instructions for this conversion? If so, where? I have read a lot but haven't seen a lot regarding the flattops.

Thanks Kenny. I think you are probably right, but I haven't ever worked on a carb before. I guess this will be a first. As near as I can tell, there is no way to inspect the float while it is on the carb. I also bought a set of round tops, but it doesn't appear totally straight forward on how to swap them out. That was going to be my next question. I have searched quite a bit and it sounds like it isn't that big a deal, but again, I have never worked on carbs. A bit intimidated at this point. Bill

I just picked up a 73 240z w/ flattop carbs and it is running rich. Don't know much about carbs, but I pulled off the air cleaner and the front carb appears to have an excessive amount of gas being pumped into it. Gas is being pumped in regularly at what seems to be a pretty high ammount. The rear carb does not do this. Is this a stuck float or something like that?