JBR

On the 78, Barry Grant Street demon carb. 350 ci engine. From idle 1000rpm, when I floor it. It boogs so bad that it will back fire out the carb. I beleive too rich. How do you lean it out? I have no book or instruction. What screws do I turn and which way? Need help.

1979toy

It sounds like your bog is a lean condition to me. Check your power valve. It should be 2 points below your idle vacuum in gear. After you have set the power valve start increasing the squirter size.
Good luck with it.

JBR

The car ran great until I installed a smaller air cleaner. Then I changed the initial timing from 6btc to 10 btc. I put the 1000cfm air cleaner back on and the boog remains. Maybe I should put the timing back to 6btc. And go from there. Where are the mixture screws on the demon. I see large headed knurled,slotted screws on the sides,are they it.?

427V8

There are 4 idle screws on a demon. The are like you say knurled screws. Turn them in (clockwise) to lean them, out for more fuel.

Lars's trick of adjusting one scew too see if it's rich or lean works well.
Basically just turn one screw and see if the vacuum goes up or down. Then tweek the other 3 and repeat.

You do have a vacuum gage hooked up the manifold vacuum don't you??

Also chack the float level, it should be between the two lines in the float view window. It's adjusted with the screw / nut on the top of each fuel bowl.

Also make sure your accell pump is working and there is no slop when you move the throttle.