Alright about a month ago I decided I wanted a little more power out of my 305 (yea I know its a 305) and I put a performer rpm cam, performer intake, and a holley 670 street avenger on the car. I have gotten the thing idling now but its rich. Also I have to open the air mixture screws up to get the car to not die and it idles at 1500 there or around but its still rich. I was told that this is probably too much carb for my 305. First:

Is this too big of a carb?

Next what could I do to this carb to fine tune it to get it to work with my 305. Could I replace the metering jets to a smaller size? Keep in mind this has been a full learning experience but now that this process is getting longer and longer I need a car to drive and this is it. My second question is:

What else could I do (besides go down a carb size) to make this package work with my engine?

The help will be much appreciated. Thanks

 

i would say that is a little on the big side. time to jet her down.

go to the carb forum and look for a sticky on holley tuning. i think sofakingdom did it. its a great writeup and should help you.

 

I took the jets down 3 sizes and its running MUCH better now. I am going down a few more sizes and it should clear it up. I am really close now and Ill post later if I have a problem.

 

Ok I still need help. Something strange happened. I went down a few smaller jet sizes then my car would not start. I then decided to go back up to the bigger jet sizes and it had a real hard time cranking again. I then got it to idle but when I applied any gas the car would stall.

I am a novice at this and rebuilding my 305 has been fun but now I am getting to the point where I am getting frustrated and my parents (still live with them right now) are getting on my case and won't give me a moments peace about the car and keep telling me that I can't do it and take it to someone else.

Now I was told that there is a line that runs to the on board computer which when connected will not allow you to change the timing. Is this true with the carbed 305 or is it just on the fuel injected models? Now I know the problems I am having is both timing and air/fuel mixture. I have been told by people that my carb is too big and been told that the carb will work just fine. I just can't get over this hump to get my car driving again.

The help will be much appreciated and I will try my best to give more info on things as it is needed. Thanks.