This GS features a completely rebuilt drivetrain; the original 400 was replaced with a larger 455 engine, and a 700R4 4-SPEED automatic transmission was selected to replace the original THM 400. (The Seller has the original 400 turbo 3 speed). The 455 transplant dyno'd at 536 hp & 623 peak torque (dyno sheet included). Big-block Buicks make some serious power, and the large bore, shorter stroke design has always made them a performance favorite. A 12-bolt 3:73 posi is a perfect choice for that pin-you-in-your-seat acceleration. The interior features original black bucket seats, console, tilt wheel, Daytona digital dash upgrade, and console.