I run a RobbMC starter , I cranks the 572 Hemi with no problem. What I have found is that a lot of guys use the body/frame as a ground . I did years ago and had slow cranking like the batteries were not up to the task. I ran a #2 cable from the trunk mounted battery ground post to the starter/ bell housing bolt. What a difference it made, engine cranked over like a new car.

it's ok to butt heads, just don't do it with a butthead