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Thread: Round top needle length?

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    Default Round top needle length?

    I'm cleaning up two round top carbs that came on a 2.8 engine in a 260 project car. Obviously they are not original to either. One carb has a damaged top, I took an original top and piston from a early 71 carb. Upon comparing the jet needle length I found the early 71 jet was about an eighth of an inch longer than the one that came off the car. Both needles are installed to the proper height.
    Were there different lenghth needles from the factory or am I dealing with a replacement? If it is a replacement what advantage do the short needles provide?
    Mark in Portland

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    Talked to Bruce @ Z Therapy today. I decided to get kits from him. As he said " If you're getting new needles in the kits the old needle length doesn't matter anyway." I'm looking forward to viewing the SU DVD that comes with the kits. I drove my first Z for 22 years and fell in love with SUs. They were the most trouble free carbs I've ever seen. Keep-em clean and check the tuning when you get bored and want to hang out with the other love of your life.
    Mark in Portland

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    Boat Anchor Repairman Captain Obvious's Avatar
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    I've seen a few of the aftermarket needles shorter than stock, but as long as the needle is long enough that there is still needle sticking in the nozzle even with the piston all the way up, then making it longer doesn't really matter.

    However, if the needle is so sort that it pulls completely out of the nozzle when the piston is all the way up, then that's a problem.

    Does that make sense?

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    Makes perfect sense. I got my kits from Z Therapy this weekend. When I compared needles, the factory early 71 needles were the long ones.[1/8"] The new needles[SM] from Z.T. were the same length as the ones I'm replacing. I'm betting that the old ones came from Z.T. too. The car lived 1 hour south of Salem. Anyway, it's time to learn how to get the nozzles centered so that I can hear this engine run.

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    Cool. Good luck with it and here's hoping everything works out as intended!

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