|Production||Color & Trim||Engines||KwikSpecs|
Although the horsepower rating between the two engines is awful close, this was a popular tactic in the late sixties and early seventies to under rate the engine's power. Insurers were charging heavy premiums for high horsepower cars, so this was the manufacturers loophole. Torque peaks for the R/A III and IV are 430@3400 and 445@3900 respectively.
Ram Air engines also received additional finese during assembly. Components were carefully chosen and held to higher tolerances than the other engines being put together in the engine plant. Although the engines were not "hand assembled" so to speak, the engines did recieve that something extra to bring them as close to the blueprint standards.
The Ram Air IV featured specific cylinder heads, camshaft and a power peak of 5500 rpm vs 5000 rpm. The casting numbers for the Ram Air III engines are listed as #'s 12 for the manual exclusively, or 12 and 13 for automatics with the R/A IV engine got the legendary 614, a short lived but highly desirable cylinder head. All Ram Air heads got the oval shaped exhaust ports while 400's in lesser Pontiacs had traditional "D" shaped poats. The camshaft part number for the base was 9779068 and the Ram Air IV was 9794041. The lift and duration for intake/exhaust for the R/A III engine is listed as .414/.413 inches and 288/302 degrees. At .527" lift for both intake and exhaust with 308 and 320 degrees of duration, the Ram Air IV engine was a much wilder beast. Rocker arms, with a ratio of 1.65:1 were fitted to the RA IV. All Ram Air engines also received push rods that were 11/32" in diameter (versus 5/16" in other Pontiac engines) for greater stiffness in light of the more aggressive camshaft and higher valve spring pressures. Because of the higher lift of the RA IV cam, the overall length of the intake valve was 5.207" vs. 5.093" for the RA III.
Sparking the engines was one of three distributors. The RA III manuals received the part number 1112024 unit with a hardened drive gear. With the RA III/auto trans combination, the distributor was pn 11120009, while regardless of the transmission, the Ram Air IV's used the 1112013 distributor with a cadmium gear. Both engines still used points and condenser (remember them?) with the point gap at 19-thousandths. After the spark left the distributor, it ended up sparking AC R44S plugs set at .035".
Either engine could be mated to either a 4-speed manual or three speed automatic transmission. The Ram Air III was available with a pair of manual transmissions, either the M20 wide-ratio or the M21 Close-ratio. Only the M20 wide ratio transmission could be teamed up with the RA IV if you wanted to shift yourself. The automatic GM's nearly bullet-proof Turbohydramatic 400. The four-speed carried a "Hurst" shifter with a thin tapered shift knob and a long (too long) handle and corresponding throw. Shifting the manual quickly was a chore, but with determination, it could be done. The four speed introduced the term "tennis elbow" to car guys, with the long shift throw and the location of the console armrest pad, let's just say some discomfort was bound to happen.
The famed 12-bolt GM rear axle was only available in the 1970 Trans Am and was available with four popular axle ratios. The base axle ratio for all engine/transmissions except the 4-speed Ram Air IV was a 3.55:1 Teamed with the RA III, an automatic transmission, and air conditioning, a 3.08 axle was optional. When equipped with a manual transmission RAIII and air conditioning, the buyer could order up a 3.31 axle ratio. Finally, the Ram Air IV's with manuals or any other non air cars could be built with a 3.73 axle.
Chassis wise, the Trans Am carried over unibody construction with a separate bolted on front subframe. Wheelbase remained the same at a nominal measurement of 108 inches. This idea of a unit body and a subframe seemed wonderful on paper - the lightweight construction mated to the sturdiness of a "frame" to support the loads of the engine and front suspension. It was the bolting up process that caused concern however, as all second generation Trans Am had a natural hinge, right where you don't need one. This invariably caused creaks, groans, and some pretty nasty hood movements when in motion on all but the smoothest of pavements.
Handling was always a key issue, and the Trans Am came with the hardware to back up this point. Front suspension comprised of upper and lower control arms, coil springs, conventional heavy duty tube shocks, and a beefy 1.25" front stabilizer bar to keep the car flat on the corners. With a great deal of weight over the front wheels, the engineers worked hard to eliminate the "understeer" which is associated with nose heavy cars. In the rear, a large .875"stabilizer bar complemented the leaf springs, increasing roll stiffeness. The spring rates were 300lb/inch in the front and 125 lb/inch in the rear. To give the car a bit more wheel travel in the rear, the driveshaft tunnel was higher than in the 1969 Trans Ams. The result was a very neutral handling car.
Keeping the T/A firmly planted to the pavement were F60-15 bias ply tires mounted on 15" x 7" rally II wheels. The Rally II's had bright lug nuts and center cap, but were not fitted with trim rings, continuing the purposeful look of the car. The 1970 Rally II fitted to Trans Am's were unique for the year because they started with a 14" Rallye II center and added the wheel ring to it.
Bringing the big bird down to a stop was a power assisted front disc/ rear drum arrangement. The front disc brake rotors were 11 inches in diameter and had a thickness of one inch. The rotors were vented for heat dissipation and lower mass. The calipers were the single piston Delco-Moraine floating caliper introduced on the 1969. At the rear finned rear brake drums, measuring nine and one-half inches in diameter complemented the high stopping power of the fronts.
The '70 model ushered in "front fender air extractors" which were shaped to created a natural low pressure area as the air passed across the opening. This allowed air to escape the engine compartment and accomplishing two tasks: reducing aerodynamic lift and engine temperature. These were eventually copied on a variety of cars, from Thunderbirds to Hornets.
Hood scoops were another key issue. Located near the forward edge of the hood, dual air intakes that fed the air cleaner through a system of ducts on the '69 T/A. Although this was copied in principal on the 1970 Formula model, the new Trans Am had a different approach, that ended up far less functional than originally planned.
The reason the T/A got a "shaker" hood scoop was an indirect result of the S.C.C.A Trans Am racing program. When the designs were being laid out, the Trans Am series allowed the use of two four-barrel carburetors. Pontiac wanted to have a hole in the hood large enough for the carburetors, but in order to do so, this need to be a production option. But in 1970 the rules changed, outlawing such induction systems. So what to do with that big hole in the hood?
Pontiac designers came out with a novel idea to install a rearward facing hood scoop which featured a "flapper" at the opening which opened under full throttle by means of an electric solenoid, gulping in additional cool air. The scoop theoretically would pick up high pressure air as it built up at the base of the windshield, enhancing performance. This writer is very skeptical about this as it is quite a distance form the base of the windshield to the edge of the scoop (much unlike the Chevrolet "Cowl Induction" system which was right at the windshield base. Picking up air not only high pressure air from the base but air which spilled from the engine compartment out of the cowl). But who cares, as it looks great and lasted for 12 years.
While outstanding fuel mileage was never a key issue to Trans Am buyers, the fuel tank was sized large enough to go about 3 hours without stopping. On 49-state cars, the fuel capacity was 19.5 gallons, while those in the left most state, California, had to make do with one gallon less because of different fuel evaporative emissions regulations. All fuel was distributed by was of a Rochester 4MV four barrel carburetor that was fitted to an aluminum intake manifold.
As mentioned earlier, the sexy styling of the second generation cars encompassed more than hood scoops and air extractors. Single headlamps were used for the first time, made the car aggressive, yet refined. The single headlamp arrangement would last until 1977 when they would be dropped for the new rectangular lights. The endura front bumper made it's Firebird debut and combined with the low slung front spoiler, the car certainly exuded a racy look. This look was further emphasized by "wheel spats" which deflected air around the tires for less drag, and the curving concave rear spoiler. Although the spoilers and spats biggest impact to performance was the speed the Trans Am generated when sitting still, Pontiac engineers added functional performance to these items as well. When travelling at highway speeds, these aerodynamic devices neted 50 pounds of positive downforce, when many cars actually develop lift.
The European-esque body shell receive a hose of improvements over the 1969 design. A new double-walled roof panel added to safety while reducing interior noise. Another safety feature were the side door guard beams, to lessen the chance of passenger injury in the event of a side impact. As there was no longer a folding rear seat option, a barrier was added, safely separating the cargo from the passengers while adding to the overall rigidity of the body structure. As convertibles were falling out of favor in America, only a coupe was offered for the first time.
As far as colors go, your choices were limited -Polar White with blue stripes or lucerne blue with white stripes. The stripes ran the length of the car on the centerline, but instead of ending at the body breaks, they were curved on the edges and had a black/ multi-color border. Unlike the stripes fitted to the '69 T/A, the '70's were decals instead of paint. At the nose of the car, a medium sized Firebird decal was affixed, color keyed to the stripe color. Unlike future T/A models, no engine displacement decals were fitted to the shaker scoop, which by the way, was painted stripe color.
The rear spoiler design caused somewhat of a debate at Pontiac. For the sake of style, the corners were rounded and swept back. This cut down on the actual usefulness of the device. The squared off design, which appeared in late 1970 on the Camaro Z28, was the spoiler design the engineers wanted, but had to take second fiddle to the stylists. One nice feature of the rear spoiler was it's large size; this made a perfect billboard to announce to everyone that you were indeed in a Trans Am .
Inside, the '70 model was the only one (short of the NASCAR model with Recaro buckets) to feature low back bucket seats. All base interiors were finished in vinyl, with optional the optional custom interior featuring strato bucket seats. Opting for the custom interior allowed the buyer a choice between a knitted vinyl or a cloth/vinyl combination. Two interior features were introduced on the '70 T/Athat would prove to be a mainstay; the simulated engine tuned instrument panel applique and the fourteen inch "Formula" steering wheel. The engine tuned appearance of the instrument panel was copied by many other makers in later years. The steering wheel feels downright small in your hands, but the wheel surface was soft and grippy. Three spokes sprouted from the "geared" horn button, and they had three progressively smaller holes each. The steering wheel actually aided the feel of the good handling, making the steering seem even quicker.
Directly ahead of the driver was a optimistic 160 mph speedometer and an equally optimistic 8000 rpm tachometer. A clock was located with in the tach itself. Filling the rest of the instrument panel was a fuel, oil pressure, coolant temperature gauges, and a voltmeter. The instruments themselves had a large raised black ring surrounding them, cutting down on glare and lending a "race car" look to the instrument panel.
As for roominess, the car did loose some rear seat room and the front seats had a much lower seating position, when compared to the '69. The rear seats copied the front as the rear cushions have a bucket feel to them. The Trans Am was now a four-passenger (sort of) car. The doors were considerably heavier, and were thicker, owing the curvaceous body. A feature of the '69 missing from the 1970 order form was the folding rear seat option. If you needed to go away on a trip, pack light; the trunk was small and the opening was smaller.
All told, 3196 Trans Am's were built as 1970 models. For a model with a late introduction (February 26, 1970) this still amounted to nearly a five-fold increase over the introductory 1969. Of these, 1769 manual and 1339 automatic transmissioned Ram Air III T/A's were built while only 88 total Ram Air IV's went into 1970 Trans Ams. Of this total, 59 were automatics, leaving only 29 four-speeds to be built. Can you say expensive and rare?
1970 will always be remembered as a turning point for the Firebird. It went from Mustang look alike to a styling leader, a style and spirit that has yet to be topped.
|Back to Introduction||Forward to 1971|
400 Ram Air III
400 Ram Air III
400 Ram Air IV
400 Ram Air IV
Cloth & Vinyl
4-Manual Wide Ratio
4-Manual Close Ratio
RA III w/Air Cond
RA III w/Air Cond
RA IV - Standard
RA III w/o Air Cond
|Introduction||Forward to 1971|