Demon/ Holley Carb Tuning Basics
 

I'll give you a quick run down of what you NEED to do, and do it in THIS ORDER.

• Clean you spark plugs with brake cleaner. If they don't come clean, replace them.

• Take the carb off the intake manifold.

• Set the butterflys so that the transfer slots look like little squares. (They should only be exposed as much longitudinally as they are wide)

• Set the floats to the middle line.

• Get the engine to operating temp.

• Then, set the idle with the distributor. That's right, give the car as much timing as it needs to idle around 800. My car needed 18 inital. (Make sure to limit total to 36 with the right size bushing, you'll have to do the math) DONT SET THE IDLE WITH THE BUTTERFLYS.

• Buy a cheap hand held vacuum guage.

• Plug off all vacuum ports and hook the vacuum guage up to MANIFOLD vacuum (not ported).

• Set the idle mixture screws evenly to pull the highest vacuum possible at ide.

• Record that number, subtract two from it, install a PV of that number. (Ex. I pull 6.5 inches of vacuum at idle, thus my PV is a 4.5) Edit: Unless you have plenty of vacuum at idle, the rule is at least 2 inches less. But if you have a good amount of idle vacuum, the standard 6.5PV should be fine.

• Then test drive it.

• If there is still a bog during initial acceleration, install larger squirter nozzles. Go up 3 sizes at a time until there is no bog. If you get to size 40 and still have a bog, change the pump cam to a more aggressive one.

• Then read your plugs. Jet accordingly.

That should get you started. And you can do it ALL yourself.