ΔE 20.5, loose: different enough that you should pick on purpose. Foul Green is noticeably lighter, cooler than Kabalite Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Foul Green is noticeably lighter, cooler than Kabalite Green.
The same difference applies the other way round: Kabalite Green is noticeably darker, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Kabalite Green on the colour wheel See Foul Green on the colour wheel
All matches: Kabalite Green equivalents · Foul Green equivalents