www.crownvic.net/tech/headswap.htm
Clean chain, lay out straight like this: I========================================I
Mark the end two "I" links with a marker or something, get the dimple mark on the left cam gear pointing upwards (crank marking should be pointed down), advance the crank slightly Clock-Wise (~10*). Install RH head & cam with gear dimple straight up. Install chain so marked link coorisponds to dimple, then install chain on crank matching up mark on chain with alignment notch on crank gear. Install tensioning components and guides.