Those 1970 Buick GS Stage 1 cars were one of the more potent cars on the street in their day. Despite their heavily under-rated 360 h.p., they were the equal or better than a 440 Six Pack, 429 Cobra Jet, or W30 442.
I once owned a 1970 Buick Wildcat, as our family car. The 455 that was in it was factory rated at 370 h.p. GM took this same engine and plopped it into the GS, and it lost 20h.p. to 350. Then the Stage 1 option was added, with better heads and cam, to raise factory rated h.p. to 360, still 10 h.p. less than my Wildcat. That Stage 1 455 was easily over 400 h.p.
