I just got this 87 camaro yesterday, has stock 305 with stock 4 barrel carb... The secondaries won't open! The car lacks power too. I can get it up to 55 but it takes a lot longer than it should. The car starts and idles just fine, doesn't sputter or anything when giving gas... It's just slow! I know there is a vacuum leak, but that's just a hose for the emissions and shouldn't have anything to do with this... At least I don't think so... Any ideas?

 

Fix your vacuum leak then check out your carb.

I had a similar problem where anything past half throttle my car would fall on it's face and would not accelerate very well. I noticed that there is a little lever/pin engaged in the secondary throttle shaft that was keeping the secondary throttle from opening up which is normal for a cold engine. What is suppose to happen is once the motor warms up the choke mechanism starts to move and it hits this lever and then it will allow the secondaries to open up. The mechanism from the choke that would hit the lever was missing on my carb. If I tied that pin/lever back then everything worked.

 

Well today I went out there and found out the timing wasn't advanced enough so it definitely has more power but still feels slower than I think it should be, and that's after plugging vacuum leak too... Also I was "testing" secondaries today at idle, if I give it gas the vacuum lever that locks the secondaries top flap in place loosens where I can open it by hand. But the valve at the bottom of secondaries that actually let's fuel into intake, it doesn't open... It may be vacuum too though idk, I know the secondaries won't open unless car is under load.

 

Go here--> http://www.hemmings.com/mus/stories/...feature20.html

Picture #6 shows the secondary lockout lever which is what I was talking about. My choke would not move the lever away to allow the throttle shaft to rotate and open the throttle blades ("valve at the bottom"). Not saying that this is your problem but it was something to check prior to tearing into it.

The article I linked also talks about the air valve and its relationship to the secondaries. A good article to read before you get into the carb.