Culp helped invent the modern nose guard position in the NFL. He was an All-American nose guard in college but considered to short to play defensive tackle in an NFL
4-3. The Broncos drafted him as an offensive guard but traded him in training camp because he did not want to play on that side of the ball. Hank Stram and the Chiefs stole him for a middle round pick and made him a kind of nose defensive tackle..
The Chiefs at the time would shift a tackle over the center a lot. Not many other teams did this with any frequency against a 4-3. In the 60's the centers were normally much smaller than the other offensive linemen. Their primary responsibilities on runs were either to block the middle linebacker or cut a defensive tackle. On passes the center was expected to slide to pick up blitzes or help on another defensive linemen.
Stram figured he could could get an advantage by moving a defensive tackle over the smaller center. In 1969 Super Bowl year Stram would slide either Culp, who was listed at 265 pounds sited at 6-2 and 265 pounds, or Buck Buchanon, who was 6-7 and 270, over center. In the Super Bowl Culp destroyed Mick Tingelhoff, who was 6-2 and 239 pounds, and considered the perennial All-NFL center at the time.
In 1974 Houston went ahead and adopted a 3-4 as their base defense. I think the Oilers and New England were the first teams to run the 3-4 as a base defense in that year. The Oilers acquired Culp from the Chiefs in mid-season and made him the noseguard. Culp had a tremendous 1975 and made All-NFL and the defense became a staple.