So I've had my 260 for a while now, and when I tuned the carbs in the past I've used a unisyn to balance and done the rest by ear. But this week I looked up more advanced ways of tuning like using a vacuum guage and using the tabs on the bottom of the carb to lift the piston.(I also tried using a colorTune but it turned out to be the most worthless thing I have ever bought, my engine was almost stalling on the road when it told me I was in the "bunson blue perfection zone")

After using all these tests(besides the ridiculous colorTune) they all imply that I am too lean no matter what I do. Float bowls as rich as they will go and mixture knobs all the down. The car runs fine as just a cruiser, but step on it and it sounds like a dying moose.

I don't know if this would make a difference with tuning, but when I bought the 260 it came with a 280zx L28 with an earlier intake(I think from a 240) and 4 screw SU's. Any ideas?

Oh ya. And I forgot to mention that even though it says I'm lean the car still has a beautiful idle, and pretty nice throttle, but only when not under load

Try the sm needles, I had a simmillar problem the sm's cured, 30.00 for a pair at ZT.

You can roughly tune by plug colour too. It will get you close.

Are they white now?

ya... I got White plugs. So still tellin me it's lean