There were two Ram Air 400 cu in (6.6 L) engines available for the 1970 Trans Am: the 335 hp (250 kW) L74 Ram Air III 400 (366 hp (273 kW) in the GTO) and the 345 hp (257 kW) L67 Ram Air IV (370 hp (280 kW) in the GTO) that were carried over from 1969.

The most powerful production GTOs were the 1969–70 models with the optional Ram Air IV 400-cubic-inch V-8, which made 370 horsepower at 5500 rpm and 445 lb-ft of torque at 3900 rpm.

here's a little more GTO info for fun...