I am getting ready to install some new heads on my new 4.6L block that i haven't dropped in the car yet. but i am a little worried about getting the timing right, and like all motors should i have the bottom end set at TDC ( top dead center ) when i put the heads on and install the timing chain and cams, and what should i do about the new cams when i install those as well? do i just line up the timing marks on the timing chain or do i have to rotate them a certain amount of times before lining up the timing marks?????????? not gonna lie these 4.6 motors are i bit confusing compared to the Chevy 350's Ive been working on lately. any help would be much appreciated please and thankyou.