Holley Drill Conversion Chart.



Just because you know the diameter of the hole in the jet doesn't mean you should start drilling on Holley jets!
The same size hole can flow more or less depending on the tapered/ radiused edges leading into and out of Holley jets.
This drill size chart is here so you can use a drill set to figure out what all of those loose jets you have lying around are supposed to be.

NEVER STORE HOLLEY JETS ON A WIRE! The wire will expand and misshape the orifice!
Stringing them on Nylon fishing line is a much better idea, but a jet storage board is very cheap, and definitely the right way to store your extra jets.

Number, Decimal, & Fractional
Drill
Number
Decimal
Size
Fractional
Size
Drill
Number
Decimal
Size
Fractional
Size
800.0135570.043
790.0145560.04693/64
0.01561/640.04693/64
780.016550.052
770.018540.055
760.02530.0595
750.0210.06251/16
740.0225520.0635
730.024510.067
720.025500.07
710.026490.073
700.028480.076
690.02920.07815/64
680.031470.0785
0.03121/32460.081
670.032450.082
660.033440.086
650.035430.089
640.036420.0935
630.0370.09383/32
620.038410.096
610.039400.098
600.04390.0995
590.041380.1015
580.042