Carb Adjustments

[MWalker1]

I have a holley 600 on my chevy 305 and i just want to kno does anyone kno how to adjust it they say i have my air and gas mixture messed up please tell me some tips

 

[autonaut]

You need a vacuum gauge and a timing light that also shows rpm.

Perfect the timing. Then tune your carburator. Disassembly might be required.

If youre only looking for best possible idle, use your vacuum gauge and ears and eyes to asses at what point the engines is running best when vacuum off the manifold vacuum port is measured with the gauge.

 

[truracer20]

What are your symptoms? Do you know what Jets are in the front and whether the rear metering plate has been drilled? Did you purchase new or second hand? Holley carbs get a bad rap because people buy second hand and get a carb that's not tuned for their needs. If t is used and has ever been "race prepped" then walk away from it. Sometimes class rules require carbs like these and they are heavily worked over with most work being irreversible.
When I got my new Holley 600I had to go up in jet size for my mild 350 SBC went up 4 in the front and 6 in the back using a Quick Fuel secondary metering block, judging by the initial out of the box jetting it probably would have been good on a 305.
As said previously make sure your ignition is in top shape. Worn out stock distributors and Chinese aftermarket distributors can make you chase your tail while trying to tune an engine. Sticking advance weights and worn or bent shafts and gears are common issues that can cause hair loss.