There is a lot of confusion regarding dumbbell pullovers and if they target your back or your chest muscles. Dumbbell pullovers can target both your pecs and your lats if you change their point of emphasis by making tiny changes in the way you perform them.
To do a dumbbell pullover, grab a dumbbell and sit on a bench. You will need a lighter weight, one that will strengthen your mind-muscle connection with the muscles you intend to work on with each of the techniques. Lie down on a bench and hold the dumbbell with both of your hands forming a diamond shape between them and slide back so that your head is hanging off the edge of the bench. Keep this position for all dumbbell pullover exercises.
The difference between the dumbbell pullover exercises that target your chest from the ones that target your lats is the bend in your elbows when you perform a rep. When you want to work on your pecs, keep your elbows in and your arms as straight as you can while doing the exercise. Lower the dumbbell down as far as possible and lift it up the exact same way. When you get to the top of the movement, flex your pecs and keep pumping out reps just like this until you reach your goal.
When you want your dumbbell pullovers to affect your back muscles, slightly flare your elbows and make sure to keep the dumbbell as close to your body as possible, which means your elbows are going to widen even more. When you get to the top of the movement, flex your lats and stop before the dumbbell reaches your chest.
You might need to practice a few times to get that mind-body link, but make sure to get a lighter weight, do both options and see how your muscles react. With enough practice you should soon be able to do this exercise for both body parts whenever you want.