Here are a couple of interesting quotes from the Gary Lisk 2nd generation Trans Am page about the 79's speed, with reference to it's aerodynamics in the 2nd paragraph:
As for the final iteration of the 400 (coded WH ), the rear end gearing was scaled back to 3.23:1, again for fuel economy, but this also allowed the '79's to go a bit faster on the top end. During road testing Car & Driver magazine sent the tach past the 5000-rpm redline to reach 132 mph at 5400 rpm. This was one of the last cars whose top speed was gearing limited rather than drag limited. The engine was still willing and trust me, has enough torque (320 lb/ft @2800 rpm) to take off in third gear, when brain faded individuals such as myself pick the wrong gear. (As much as the Hurst shifter impresses the heck out nearly everyone who sees the gleaming chrome stalk, it doesn't work as good as it looks!)
Performance wise, the 1979 edition made some impressive gains. Due to the slightly higher gearing, the 220hp engine was a bit slower in the quarter mile, taking 15.3 seconds to cover the distance, a tenth slower than the '78. The better aerodynamics came in to play with a higher trap speed of 96.6 mph, 3.2 miles per hour quicker than the '78. The 0-60 mph times for the '79 picked up a half second requiring 6.7 seconds for the sprint. The new four wheel disc brakes of the WS6 cars knocked a yard from the stopping distance, bringing the Trans Am down from 60 mph in only 146 feet. In February of 1979, Hot Rod magazine tested a Pontiac Engineering prepared "press car". This car may have been a warmed over "ringer" as the T/A 6.6 powered 4-speed thundered down the quarter mile in 14.61 seconds @ 96.67 mph. Even HRM admitted that a typical TA of this type could expect time slips in the 15.30 range.
