One head oils when #8 is firing (DR side iirc) & one head oils when #6 is firing. going by the rotor position with a 1&1/4" socket/breaker bar turn to whichever of the two is closest & preoil then hand turn to the other position & preoil. I like to do 8 first then go 3/4 turn clockwise to #6 (timing slit will be on zero on the timing tab) & when done preoiling that side then back up the crank CCW slightly to 10 BTDC mild cam/15 wild cam) & clock the intergear so the rotor is under #6 & the magnet is dead even with the tooth