Kad77

Thanks for the help! I just ordered those needles you gave the link for. Once they show up, I'll install them and give an update on the results. Thanks again!!

Sorry for no updates for awhile. I dug into the carbs and figured out that my float levels were completely off. One was set very rich and the other was set very lean. After properly setting the float levels, the car accelerates much smoother and does not feel like it is going to rattle itself apart above 4500 rpms. It will rev up to the yellow line now, and has better power above 4500 now, and it is smooth revs. It still feels like it is missing some power above 4000rpms, but it is way better than before. I believe the issue is that my carbs are still running lean. No matter what adjustments I make, they run lean. I do have a very small air leak at the butterfly valve shafts. Not much I can do about that right now. Z therapy carbs are out of the budget at the moment. I have not yet purchased SM needles, I will do this soon, and i am hoping that they will help get the carbs to run a little more rich. Thanks for all the help! Any further advice is appreciated!

Thanks for the reply! How could the wiring be screwed up for the fuel pump? As far as I understood it, it was simply two wires. When I first got the car running, I didn't have a fuel pump with high enough gallons per minute and the car would shut off under load. I upgraded the fuel pump, and it seems to do the job. It is a 4-7psi 30gpm pump. Do you think this is enough? Thanks!!

I'm in Salt Lake City, Utah. So around 4000-5000ft elevation. The car has always been like this since I rebuilt the engine. Prior to the rebuild, the car did not run. I bought the car non running, and had to rebuild the engine after realizing it was toast. Thanks! Any advice is greatly appreciated!

Thanks for the reply! Yes, my engine will rev to 6000 when not underload. But it still feels like flat power after 4000. While driving, it will I've revved it to 5500, but above 4000, there is just no acceleration. I've got brand new fuel filters on mine as well. The old ones were definitely clogged. Any advice is appreciated!

Thanks for the reply! So I just set the timing yesterday. Since I currently have a tank of 87 octane in the car, I set the timing to stock 10* BTDC. Once I'm through this tank of gas, I'll fill up with 91 octane and advance the timing. There was some backfire and popping on deceleration. So yesterday I pulled the plugs and there were a little white. So it was in fact running a little lean. I richened the carburetors a little by turning the adjustment on the bottom of the carburetors. This seemed to help with the popping. It now decelerates without popping, or at least significantly less popping. I synced the carbs when I first rebuild the engine. I've checked them once since then and there were still synced. Any further advice is greatly appreciated!

I have a 1978 Datsun 280z. I rebuilt the engine last year. Removed the fuel injection and installed 240z SU carburetors. The car starts and runs great, I typically use it as a daily driver. The only problem I have, is that I hardly ever rev it above 4000 rpms. I watch videos of people driving Zs and they always take it up to 5000 or even 6000 rpms. But for my Z there seems to be no additional power or acceleration above 4000rpms. There doesn't seem to be any stumbles or misfires, it just seems like the power is flat above 4000 rpms. I thought Zs had power all the way to the yellow line. I've never driven another Z besides mine, so I do not know for sure. Any advice is appreciated! Thanks in advance!