Don Terrill’s Speed-Talk

where should the float level be on a holley on a drag race car. i set mine so it just trickles out the bottom of the sight plug. my buddies say that is wrong and they have the glass sight plusr and they set theirs at 1/2 to 3/4 up the site plug and their cars always seem to be idling way to rich. what is the proper setting. im sure there will be lots of answers thanks art

My carb guy sez1/2 way upon front 3/4 on back

thanks red you are the first. i guess you need the glass sight plugs to see you method of adjustment. i have broken them clear plugs many timesin different carbs. they are too fragile for me to use thanks art

Well back in the day when you had the standard brass plug it was just when it trickled out the hole and they ran fine. That's how I adjust mine especially on the street. Higher level will richen things up a bit.

I don't have two bowls in front of me but I think the screw in plugs are smaller and higher than the actual see thru sight plugs held in with a snap ring(not the screw in sight plugs for older style bowls that came with brass screw in plugs).

If so it's would make sense to set the brass plug style just trickling and the glass at half to be about the same.

I was told by my Alky carb builder to ignore the holes and set the float level with a 7/16 drill bit in between the top of the inside of the bowl and the top of the float. Always worked for us.

One of the few good things about a Holley is the externally adjustable fuel level/ sight plug. Fuel pressure & needle/seat size affects the fuel level.

Using a fixed dimension like drill bit to set fuel level will only work with a certain combination of fuel pressure & n/s.

Carter published a chart of fuel pressure & n/s size so that the float level on Carter 4bbl carbs could be correctly set.

The gauge pin method is the best. Either will work but you must be aware that changes in the fuel level will change the A/F ratio.

You must be aware that not all bowls have the sight hole at the same height they are all over the place.Pin method works for me.

Fuel just slightly dripping out of the bottom of the plug hole has always worked for me. More important is to have good fuel delivery system (volume and pressure) from the fuel tank to the carburetor (s) and a needle/seat assembly that will insure that plenty of fuel is delivered to the bowls during a run.