My brother's car is running poorly. The idle is around 1200 in park and the car has no power. Today, he floored it from a dead stop and he barely spun the rear tires. A little while ago, he would have smoked those babies all day long. A little while ago the car was running fine and then one day it started to run bad. He has a stock zz3, HEI, and a 650 Holley with electric choke. He already changed the plugs and wires, and the car did not run any better. The initial timing is set at 14 degrees btdc. If he tries to go any lower, the engine will die. He tried turning the idle screws down, and the car still idles high. Everything was new when he bought it and the car ran fine for years. I thought he had a vacuum leak, but I'm not sure. Could the carb need to be rebuilt. The car was restored 7 years and the carb/engine were new. I doubt that he has put more than 8000 on the car since he restored it.

Sounds like a classic case of a vacuum leak. I would look for the standard culprits, carb base plate, all vacuum hoses, the connection at the brake power booster if so equipped..

I would check/replace all of these items before moving forward.

That's what I thought. When ever my brother gets any free time, I think will start checking for the vacuum leaks first. Thanks