The Trans Am has established itself as a permanent American icon. Production volume testifies that the Second-Gen Firebird was most popular with consumers. Its combination of beautiful styling, superb handling, and strong Pontiac V-8 performance makes Formulas and Trans Ams of this era highly coveted by collectors and performance traditionalists alike.
Living up to its hype wasn't always easy, though. For example, the standard engine for the '77 was the L78 400ci four-barrel. A compression ratio of just 7.6:1 and restrictive exhaust strangled the once-potent mill to a paltry 180hp rating, and when combined with a high-ratio rear axle, the performance flagship was a shadow of its former self. To regain some power, the W72 Performance Package became an extra-cost option on Firebird Formula and Trans Am models.
It included the new T/A 6.6 engine, which was rated at 200 hp-an amount equal to the last 455 of '76. It did so by using a specific Rochester Quadrajet carburetor and HEI distributor, an increased compression ratio, and a redesigned camshaft with unique valve timing. The package also included a tuned exhaust system and 3.23 gears, and it produced a Trans Am that could compete with virtually any new vehicle on American roadways.
Further camshaft timing and exhaust revisions gave the T/A 6.6 a boost to 220 hp for the '78 model year. To increase the Trans Am's performance prowess even more, Pontiac released the WS6 Suspension Package that same year, which included specific springs and shock absorbers, stiffer suspension bushings, a constant-ratio steering box, a larger rear sway bar, and 15x8-inch aluminum Snowflake wheels. Together, these packages took the Trans Am from what many already considered an excellent performer to exceptional, propelling it toward supercar status.
The proverbial writing was on the wall for large-cube engines. Pontiac discontinued its 350 after the '77, and General Motors decided that the Division no longer needed its 400 and planned to phase it out of production during the '78 model year. That left the short-deck 301 as Pontiac's only V-8, which remained in production through the '81.
In an attempt to maintain the Trans Am's strong performance image, Pontiac managed to stockpile several thousand 400ci blocks to use as T/A 6.6 engines in the '79 Trans Am. A buying frenzy erupted as news of the 400's discontinuance spread throughout the information pipeline. A total of 117,108 Trans Ams were built in that year and just 8,326 of them received the T/A 6.6 engine. The remainder received the Olds-built 403 or Pontiac 301.
The Trans Am's original No....
The Trans Am's original No. 17059263 M4MV Rochester Quadrajet offers a maximum airflow capacity of approximately 800 cfm. The black shroud is designed to keep airflow away from the carburetor and choke.
A High Energy Ignition (HEI)...
A High Energy Ignition (HEI) system was standard fare on all Pontiac models beginning in 1975, and this particular unit, No. 1103315, is specific to the '78-'79 T/A 6.6 engines. Pontiac's 1979 Service Manual Supplement states that it provides 17 degrees of centrifugal advance by 4,600 rpm, along with 25 additional degrees of vacuum advance.
Power brakes were standard...
Power brakes were standard equipment on the Trans Am, and this particular unit controls the discs that reside at all four corners. Notice that the master cylinder wears its original black paint.
T/A 6.6 Anatomy
Essentially a carryover from the previous year, the '79 code-PWH T/A 6.6 was assembled using a No. XX481988 400 block, which featured a 4.12-inch bore. Its bottom end was filled with a 3.75-inch stroke cast-iron crankshaft, while cast-aluminum pistons on cast-iron connecting rods filled the cylinders. A 60-psi oil pump dispersed lubricant, and resided within a baffled six-quart oil pan.
A top each cylinder bank sat a No. 6X-4 cylinder head, which was otherwise associated with 350 engines. It featured 2.11/1.66-inch intake and exhaust valves, and combustion chambers that displace approximately 91 cc's, which bumped compression to 8.0:1. Though Pontiac never divulged the 0.050-inch duration specifications of the No. 402 hydraulic flat-tappet camshaft, independent testing shows it to be approximately 192/210 degrees, with 0.395/0.0400-inch gross valve lift with 1.5:1 ratio rocker arms.
Distributing the combustible air/fuel mixture from the 800-cfm, No. 17059263 Rochester Quadrajet carburetor was a No. 10003395 cast-iron four-barrel intake manifold with EGR. A pair of log-type exhaust manifolds routed spent gasses through a single catalytic converter and into a "Y" pipe and dual mufflers before it exited out a pair of chromed splitter tips. The net result of the effort was a rating of 220 hp at 4,000 rpm and 320 lb/ft of torque at 2,800 rpm.