The El Camino Real Derby (USA-G3) winner Metaboss is the more experienced of the pair with five starts under his belt. Both his wins have been at 9 furlongs, and he handled the distance in the El Camino Real with complete authority, turning in a final furlong under 12 seconds. The good news is that he has demonstrated that he doesn't need a pace meltdown up front to be able to deliver a strong finishing kick, and his closing run was the more impressive in that it appeared that he had to check slightly as he was coming around the field. The bad news is that he still has to show that he can close ground on dirt and against better horses if he is to be a Kentucky Derby contender.
Although he is by the sprinter Street Boss, Metaboss has a potent stamina influence close up in Bien Bien, the sire of his second dam. Bien Bien, a son of champion turf horse Manila, showed near-championship form himself and among his other accomplishments set a course record of 1:57.75 for 10 furlongs at Hollywood. He also won the San Juan Capistrano Handicap (USA-G1) at about 14 furlongs, so lack of stamina was not an issue with him. In fact, his progeny's average winning distance of 9.3 furlongs indicates too much of a staying preference for success under American conditions.
Free House, Metaboss' broodmare sire, stayed well enough to place in all three Triple Crown races and later won the 10-furlong Pacific Classic Stakes (USA-G1) and Santa Anita Handicap (USA-G1) but is more of a question mark as to how much stamina he might have contributed. His progeny AWD is only 6.7 furlongs, though this may be a reflection of the population of mares he saw as well as his own proclivities as a sire. My best guess regarding Metaboss is that another furlong won't be a problem, but whether he will be able to transfer his turf/synthetics form to dirt is another question.
Power Jam is the other West Coast 3-year-old to turn in a strong performance on Saturday, breaking his maiden at first asking in a snappy 1:08.68 under a hand ride. Like Metaboss, he has a pedigree that suggests the possibility of stamina but doesn't guarantee it. More ominously, he is much less experienced and has little time to either gain seasoning or stretch out bit by bit.
Concord Point, Power Jam's sire, won the 9-furlong West Virginia Derby (USA-G2) but never made it back to the races after that win, leaving the question open as to whether he might have stayed further. Given that his dam has consistently thrown horses that preferred a mile or less even when bred to staying sires, it seems likelier that he would have proven a high-quality miler with the cruising speed and athleticism to tack on an extra furlong rather than a true mile-and-a-quarter horse.
On the distaff side of things, having Smart Strike and A.P. Indy as the first two damsires suggests the possibility of Classic stamina, and Power Jam is actually inbred 4x3 to A.P. Indy. Having 1992 American champion 2-year-old filly Eliza as the third dam is another question mark, however, for 8.5 furlongs proved to be the limit of her tether and only her foals by the long-winded Theatrical showed any taste for more. Power Jam's second dam Day Lily is an enigma as she did not race, though she threw foals that preferred routes by Mr. Greeley and Distorted Humor. Power Jam is the only foal to race for his dam Musical Rhythm, also unraced.
Ultimately, while Power Jam may prove he can stay further down the line, I doubt it will be in the Kentucky Derby. Asking him to develop the seasoning he needs to stretch from 6 to 10 furlongs in less than three months is a pretty tall order, and the light, quick action he showed in his maiden win seems better suited to shorter trips. He may develop the ability to relax into a more ground-eating stride as he matures and gains experience, but the Derby is probably going to come too soon for him.