I just bought a 1984 Z/28 with the L69 yesterday. My plans are to drive it until I get my 91 L98 Z/28 built, then build this one. But I have having a little difficulty. I'm not very experienced in carburered cars, so let me say what's going on. It now has an Edelbrock 650 4 barrel carburetor. Every time I crank the car, the car idles high, around 2500 rpm, then drops to 2000, then about 1500 rpm. Every time I give it gas, the choke opens, and the car cuts off. I do know you have to let carburered cars warm up, especially in cold winter, but it's doing this 15, 20 minutes with the vehicle running. I drove it home, about 30 miles from where I bought it, and every time i push in the clutch (its a 5-speed car) and slow down, either to turn, or to stop and let the car idle, the car cuts off. I constantly have to keep the engine over 1000 rpm to keep it running. Any help would be greatly appreciated

 

I did forget to mention that I just replaced the fuel pump and the fuel filter on this car. So those parts are brand new.

 

My first suggestion would be to put the original carb back on.

If for whatever reason you don't do that, then check for vacuum leaks. Since an Edelbrock will not bolt directly to a stock intake manifold, the manifold was either replaced with an aftermarket intake with squarebore bolt pattern, or a spreadbore-to-squarebore adapter was used. Both invite vacuum leaks.

Oh, was the distributor changed when the Edelbrock downgrade was done?

 

I had a similar problem with my carb. I have a holley 600 cfm 4 barrel. Slowing down killed it completely. I took off the rear bowl, reset the fuel delivery tube to the rear bowl and opened the choke all the way and it worked fine. I guess the choke flap would shut when braking hard and starve the engine of air thus stalling it. Brake booster vacuum leaks will kill your car. Just go through and trouble shoot possible vacuum leaks.

 

Thanks you two for the advice. Wasn't able to put the original carb on, because the guy who owned it before the guy who owned it before me (dating back) put a 750 on it. Then the guy before me put a 650 on it, so that's how I got the car. Apparently, when he put the carb on, he didn't tune it or adjust the idle screw and the air/fuel mixture screw. Doing some research on here, other people have said to try adjusting 4 screws out, and fine tune from there. So I set them all the closed, which were both at 1 screw out. Set both screws 4 screws out, and it seems to be doing fine. Now I just gotta through a thermostat in it so I can drive it.