"It was outstanding," Astros manager Bo Porter said of his team's offensive output. "Guys got into good hitting counts. I think the off day served them well. They were able to drive some balls."
Rick Ankiel went 2-for-4 to improve his spring average to .435, and the Astros had 13 hits.
Nolasco, the Marlins' Opening Day starter, faced 14 hitters in the first two innings. He allowed seven runs on eight hits and two walks in three innings. He threw 68 pitches, 40 for strikes.
Nolasco gave up three runs in the first on Pena's two-run homer that carried over the right-field fence and Wallace's solo shot to center on the very next pitch.
It didn't get any better in the second for Nolasco, as Dominguez crushed the first pitch he saw to left for a two-run homer to give the Astros a 5-0 lead. Carter had an RBI fielder's choice to make 6-0.
Castro's solo shot in the third made it 7-0.
Astros starter Bud Norris ran into similar trouble in the third. He gave up two singles to lead off the inning before Chone Figgins' RBI groundout. Donovan Solano followed with an RBI double, and two batters later, Kevin Kouzmanoff hit a two-run home run straightaway center field as the Marlins closed the gap to 7-4.
Norris was charged with four runs on seven hits in 3 2/3 innings.
It was Kouzmanoff's third home run of the spring, while Solano continued his red-hot spring, going 2-for-3 with a single and the double, to raise his average to .500 in Grapefruit League play.
The Astros' home run barrage continued even when Nolasco departed, as Carter went yard to lead off the fourth against Mitch Talbot to make it 8-4. They added a run in the sixth on Wallace's RBI double to left. Wallace was 2-for-5.
Phil Humber pitched the final five innings, allowing only a leadoff double to Kouzmanoff in the ninth, with three strikeouts. His spring ERA is 1.29.
Up next: Houston's Jordan Lyles, who is 0-3 this spring, starts when the Astros play host to the Nationals at 12:05 p.m. CT on Wednesday in Kissimmee. The 22-year-old right-hander has surrendered 12 runs on 17 hits over 2 2/3 innings in two of his three appearances. Washington counters with Ross Ohlendorf. The game can be heard live on Gameday Audio.