I think what he is referring to is an expensive ($250.00+), high revving, high horsepower enigne such as an:

OS VZB V-Spec T
Novarossi/Top/Rex Plus 5 or Plus 5X (aka P5 or P5X)
RB Concept C5 or C5 BB

These engines are pretty much the best when it comes to 1/8th buggies (aside from the hand modified versions of these engines). The larger displacement engines, such as the Sportwerks .26 are considered outlaw engines because their displacement is too big for sanctioned racing events.

The outlaw engines can put out horsepower numbers to rival the race .21s listed above, but don't typically rev as high. They also make a considerable ammount of torque. This higher torque/lower RPM makes them better suited for use in truggies/monster trucks where torque is needed to spin the larger tires, and less RPM is needed because the big tires provide a longer roll out. For buggies, you want as many RPMs as you can get.