Thread: 305 running rich

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Sniper – The Edelbrock carbs tend to run a bit rich out of the box. Great for turbo motors and some combinations of aftermarket cams and heads, but with your basically stock (low compression) 305, some tuning is required.

What you probably have is an Edelbrock 1403 carb, which is actually a 500 cfm electric choke model. Interestingly enough, they have been sold as 550 cfm as well. If it is in fact a 1403, you can use the drawing below to diagnose your condition and remedy with a jet and probably a metering rod change. Verify the number as it is important. The next step up is a 1406, 600 cfm that uses larger main jet.

I would suggest that you change the metering rod to#1463 (.067 x .052) as this can be accomplished in five minutes without opening up the top of the carb. If you’re still rich, I would go to a #1422 Main Jet (.083) and this will almost certainly address problem. If you change the jet, remember to buy a new gasket – even if the carb is new – as it can stick and tear when the top of the carb is removed and will leak. Nothing worse than having to go back to the store for a gasket!

Before you start, down load the manual here:

http://www.edelbrock.com/automotive_...ers_manual.pdf

For the first time reader, it’s a bit confusing but pour a cup of coffee and study it before you start. Pages 20 and 21 are critical for you to understand if you have not taken these carbs apart before.

Good Luck!
Glenn