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djhedges

Racing Flat Top Carbs

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Has anyone had any experience or tips for tuning these carbs for specifically for racing?

I recently bought a ITS prepped 260z with the flat tops. All the emission stuff is plugged and the choke removed. The car has EGTs which show about 1100F at WOT on the straights. Last weekend we had a test and tune day at Oregon Raceway Park. The track is at about 2300ft elevation and the temperature was in the low 40 to mid 40's that day.

We pulled the carbs and measured the needle at 45mm. We tried moving the needle to 45.5mm, 46.5mm and backwards to 44mm. EGTs still read 1100F except for the 44mm which was at 900F.

Tomorrow we're planning to check the valves and do a compression test.

What oil do you guys run in your carbs? How much oil? Got any other suggestions?

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If you want a spare set, I'll sell you the ones I pulled off for their scrap value. I was thinking of making a set of lamps out of them. Get a set of 3 screw round tops and go racing on race day, instead of tuning every day.

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"Tony D" says he can make flat tops out perform round tops. He is on this board, but it's easier to find him on zcar.com or hybridz.org. I too have a box of flat tops. I went with round tops for my 260Z race car.

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