fill me in

I am looking for a balance tube from any year and linkage.

What are the largest rotas you can use without having to cut your fenders?

I very recently purchased a set of performance headers with a full exhaust from a friend. This is my first major engine upgrade for my 78 z. The car was working perfectly fine when we attempted to put them in. We tried to go from below but they wouldn't fit. There was no way to take it apart without cutting it. So I took the intake off and slipped the sucker right in. I replaced the gasket with a fresh one and started to put everything back together. All of the spark plugs are in the right firing order and the exhaust rebreather is plugged. Everything was set to the way it was and when I went to start my car it would only start after I give it some gas. My fuel pressure is at 35 psi. After it starts it idols at about 800 then to 1200 rpm then dies. I have an idol adjustment screw for my throttle-body that i messed with before i even took off the intake. My question... Whats wrong. I dont believe that i didnt make a proper sealing with the manifold and even if i didn't, would this this cause this? Like i said the car was working just fine before this so i dont think its the maf or fuel pump... any input would help