Want to set timing on 89 5.8 liter EFI. The timing should be 10 BTDC. The crank pulley shows -10, 0, +10, +20, +30, +40 but doesn’t indicate which is before or after top dead center. Which 10 is BTDC; the -10 or the +10? Thanks

 

+ is advanced aka BTDC

 

You will not have a 20 or 40 degree mark on the after side, they will be on the BTDC side