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Howdy Yall, I've been driving my Z for a couple weeks, (its too much fun, dont want to drive other cars now). Ran into an issue that I cant seem to get myself out of. I'm getting what appears to be a lean condition on the carbs, the motor will produce a backfire/bog down when running between 2.7-3.5k RPM, and if i get to 40 mph it really drives rough. I parked the car for 2 weeks and have been trying to get a baseline tune on the carbs, based on information that I'm finding on the web, but am a little confused from the information that I'm reading online regarding the float settings: Idle ~6-750RPM @ 20mmhg on the flowmeter apparently for this carb (1970 4-screw), the instruction set that came with the carb rebuild kit states that I should be at 10.38mm on both front and rear carb, online readings indicate that the rear should be configured at ~2mm lower than the front, but the 1970 4-screws have equal length float arms, and the new floats that I got have longer floats needles in the front, while the float needles that came with the carbs are equal length front and rear. When I end up placing a new (aftermarket) float needle into the rear carb, and set it to ~10.38mm FROM THE FLAT PLATE THAT THE FLOAT NEEDLE SITS ON, i end up with a sunk float needle, which leads me to believe that the configuration is incorrect. I think adjusting the float level correctly would be the first thing to do in order to get the mixture configuration correct, does anyone have some input, or maybe some settings that work for their 4-screw? Should I switch the manufacturer for the float needles? Really want to drive it