If you are talking Q-jet, the one straight off the back of the carb goes to the vacuum storage container on the firewall. There may be a nipple sticking staight up from the base on the passenger side. That one goes to the secondary choke pull off. Those are the only lines on the back of the carb. I noticed you only have 3 posts. You might want to fill out the profile page, and add a signature, so that your name, and your car(s) come up every time you post.