Timing covers need to come off. You will need to re-time the engine. It's not that bad of a job, just do some research before you dive in, or have a shop manual around handy.
LOOK at the front seal (depending on the type) after you install it. I had a buddy replacing his front seal while I was doing the engine top this weekend, and his aftermarket seal from a known SHO vendor SPLIT & blew out. It was total carp, a cheap POS seal. We scurried around to find a seal from another SHO guy somewhat locally to get him back on the road. I didn't get to see it before he buttoned it up, but I don't think he mis-installed it. It was visually obviously blown-out after firing it up, seeing the oil **** out of there, & tearing it down again. after removing the seal, I could see where it tore at a seam in the seal, and the spring behind there was sucked out of it.
Good luck!