my ITS 73 240Z came with both. the race floats look like the needle is shaved. whats the difference? and why use the street floats at all?

new to z cars.

thanks,

-james

James,

The shaved, or tapered needles allow more fuel to enter the carburator which will provide more horsepower in a properly built up engine. There has been a lot of tuning and dyno time on needles to find the best taper.

The floats are pretty insignificant as long as they are properly adjusted and you don't have too much or too little fuel pressure.

i was told that because it runs rich, it can foul the plugs. i popped them in today and it seems to run less smooth below 3K RPM.

-james

James,

Yes, being too rich can cause many ill effects such as poor gas mileage and fouled plugs. Here is a simplified picture of a tapered needle:

Make sure the taper is 'aimed' at the incoming air. Also, make sure the needle is properly mounted at shoulder level. You may need to adjust the mixture nuts on the bottom of the carbs at idle to help with the low RPM richness.

thanks for the great pic!

whats a good book about carb tuning for that car? ive had EFI cars lately and never learned much about dual carbs.

-james

73 240z ITS

65 FFR cobra

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