Two reasons Jack was able to play conservatively:
1) His prodigious length and control let him tear up the par 5s, which were more like long par 4s for him;
2) His tee-to-green play and putting were so good, he didn't make many bogeys on the other holes. He played a lot of regulation golf there, i.e. fairways, greens and two putts.
So go a few under each round on the par 5s. Play the rest of the course around even par. You average 69 to 70 for the season, without risking big blowups.
And when you to turn on the after-burners, like the last nine holes in 1986, if you're Jack Nicklaus you certainly have the horsepower to do so.