I have a 72 datsun 240z with dual weber 32/36 dgv carbs. We ran it a couple times when we tried to drive it with dirty carbs. When we took everything apart and cleaned them, we started it and it went straight up to about 3500-4000 rpms. We checked all the hoses and lines but we couldnt find out why it was doing it. Any ideas?

You might have got the trottle linkage set up wrong and one of both carbs in not going to idle. Make sure both carbs can close fully when to let off the throttle. Also, vacuum leaks can cause high idle if the idle mixure is very rich for some reason.