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Soul survivor. These two words best represent the 1975 Trans Am at it's fall of '74 introduction, it was announced that there would be no more 455 engines. The previous years sales and attitudes had predetermined the fate of the 1975 edition. The big bird was still on the option list, but the big motor was missing... or was it?
At the long lead press preview for the 1975 models, Pontiac jubilantly announced that the 455 CID engine would not be offered. The buyers did not want the big displacement engine any longer. So they said. The journalists in attendance differed in opinion, stressing the need for the car such as the Trans Am to have a performance motor.
More on engines later because a restyling of the rear window was the big and truly welcome news for 1975. If there was one area the Firebird's and Camaro's lacked when compared to the first generation cars, it was in the rear 3/4 visibility. It was horrible. The rear quarter windows were missing and with the combination of the extreme rake of the rear backlight and tiny outside rear view mirrors, changing lanes was a matter of easing over and gritting teeth.
The new rear window alleviated some of those concerns. The rear window now came down at a 90-degree angle and went back until it reached the base of the back glass. This increased visibility while also improving the "airiness" of the interior, offering a "roomier" feeling. One area with concern of the new rear window design is rust. The front corner of the glass has a molding that is perfect for holding water, and during this era before coated alloys, rust in this area is seemingly inevitable.
GM had originally wanted this rear window to debut in the original 2nd Gen Camaro/ Firebird. Problems with the rear window installation at the factory displacing the sealer kept the rear window design out of production for three additional years until these problems were solved.
The third front end design in three years appeared for 1975. Not as drastic as the change between '73 and '74, there were changes none the less. The parking lamps were moved from below the front bumper for their first (and only) time. Filling the outboard edges of the grilles, the chrome bezeled (yes they're back!) park/turn signal lamps rested. Rather clumsily, Pontiac chose to leave the previous year's park lamp depressions, adding a "fake" screened filler in their absence.
Colors availability exploded on the Trans Am, now totalling four. The feature color became Sterling silver, complementing standbys Cameo white and Buccaneer red. Admiralty blue was replaced by Stellar blue. The standout on the traditionally quick fading Sterling silver T/A's was a dynamic red/black/charcoal bird and accompanying labels and engine callouts.
Inside the Trans Am lost the cloth/vinyl seat combination, so all interiors were finished with vinyl seat coverings. Green disappeared all together and the red trim was replaced by a rich burgundy. As in 1974, multicolored interiors could be ordered, increasing the number of potential build combinations. What the T/A lacked in go choices was made up for in the show department. The 8-track tape player was still a must have option, continuing to reside in the center console, in its own stand alone module. The base level bucket seats still hade the strong horizontal pleats, it's throw back to the days of real performance.
The lone mainstay of Trans Am production, the instrument panels remained the same, engine turned applique and all. The instruments themselve's however, took a drastic change. Gone was the oh-my-God 160-mph speedometer, replaced by a more realistic (but sad) 100 mph unit. The speedometer change was in response to the ever tightening government's noose. Theory was, if we only put a speedometer that reads up to X mph, then Joe Public will only be tempted to go X-mph. Guys, this is a Trans Am; give the people what they pay for.
Inadvertantly, they just might have. It seems a wheezy 185 hp 400 was the base motor, (it's power nearly halved from the Ram Air IV hey-day) barely had enough horsepower to make a speedometer which progressed past the 100 mile per hour mark an issue. Not only was the power produced utilarian, but so was it's power band, peaking at a mere 3600 rpm. With days of 3.73 gears long since gone, this meant it's power peak would be achieved while cruising at about 60 mph. The torque peak of 310 lb/ft at 1600 rpm was more suited for the axle ratios of the current period, giving a nice thrusty feel at the national speed limit of 55 mile per hour. If a Turbo-Hydramatic 350 was mated to the 400, the engine was coded YS . Applications the called for the 4-speed manual go the WT coded engine.
Once again a new cylinder head casting number appeared, this time they were 5C and carried last year's 2.11 inch intake and 1.66 inch exhaust valves. The camshaft fitted to all 400's was definitely more torque oriented with gross intake lift only measuring .377" while the exhaust increased by .001" to a gross of .415 inches. The small size of the exhaust valves complemented the single exhaust system with dual tailpipes, necessitated by the new catylitic converter. Although the T/A did in later generations sprout dual catylitic converters, to this day a single exhaust with dual tailpipes is how every Trans Am leaves the assembly plant.
As performance was becoming part of the history books, manual transmissioned Trans Am's were outsold by automatic by an almost three-to-one margin. The 400/4-speed combination totalled 6140 units, nearly as many as were built during the first three years of production. As for automatic big birds, 20,277 left the assembly area shiftless. A victim of the GM's compliance to the EPA's new pollution standards, the Turbo-Hydramatic 400 transmission was replaced by GM's venerable Turbo 350. It seems the new catylitic converter , required on nearly all GM cars was so large that the Turbo 400's case wouldn't fit. So it seems we lost the 455 and the big tranny all in the same year.
To make the 400 fit for the new emission's standards, a more consistent spark was required to burn the fuel -the HEI. HEI stood for High Energy Ignition. The new ignition replaced the conventional points and condenser with magnetic pick-up and igniter modules. The system operated reliably and introduced 35,000 volts to the plugs versus the 25,000 from the previous years conventional distributors.
Rear axle selections were becoming increasingly limited. Automatic/400 equipped Trans Ams had a 2.56:1 rear axle ratio . A 3.08 gear was included when the 4-speed was specified. Included as part of the "Performance Package" in which the 455 V8 was the major element, the ratio was a more satisfying 3.23:1
Fuel requirement was also changed. The days of "high-test" were memories and the new engines ran on 87-octane (sic) unleaded fuel. Unleaded fuel had been around for some time in an attempt to reduce the highly toxic lead emissions into the atmosphere. Now it was required with the new catylitic converter, as the lead in the fuel would attach itself to the catalyzing agents, rendering the converter useless. The converters attempted to reduce the amounts of C0x introduced into the atmosphere, converting the oxides into "less harmful" vapors. Unfortunately the sulphur dioxide that resulted for early converters made the exhaust have the horrible smell of "rotten eggs".
The diet of low octane fuel was certainly necessary, as the higher octane stuff most likely wouldn't have even lit off with the ludicrous 7.6:1 compression ratio. It is a good thing the spark did deliver 35,000 volts to the AC R-45TSX spark plugs gaped at .060 inches.
Midway thru the 1975 selling season, Pontiac finally succumbed to peer pressure and released, in limited numbers, the mighty 455 H.O. vee-eight. Or did they?
An engine termed 455 H.O. was in the option book, and by golly even said H.O. right there on the shaker. Only one small detail, it wasn't. The 455's were pulled from station wagon and Bonneville duty. But as a marketing idea, you have to give the folks at Pontiac credit. The 455 H.O. engine package was just that - a package, and it was full of Show, Go, and Whoa. For Show, the return of the 455 H.O. with engine was egotisticly displayed the displacement on the legendary Shaker. At the rear, new chrome "Side Splitter" exhaust tips let you know that a very special Trans Am had just gone by. Delivering the Go was the 200hp 455 V8 mated only to a four-speed manual transmission which turned the GR70 tires thru a limited slip 3.23 differential. Whoaing the T/A down were a set of sintered metallic front brake pads. While these pads has more noise potential and higher cold pedal effort, the increased braking performance they enabled was worth the tradeoff. All the others who threw in their respective corporate performance towels loathed. Compared to the 400, this was heady stuff.
In it's H.O. guise, the 455 now produced a asthmatic 200 horsepower at 3500 rpm while at only 2000 rpm its torque peak of 330 lb/ft was achieved. The same low compression and cylinder heads were fitted, although the cam profile patterned 1974's base 455. WX coding on the cylinder block denoted the 455. In September of 1975, Car and Driver magazine found out in the quarter mile, the 455 T/A took 16.1 seconds to travel the same distance the '73 SD-455 covered in 13.5 seconds. Terminal speed was down to 88.8 mph, versus 104. Eight-hundred fifty-seven people were lucky enough to get this engine in place of the 400.
On the twisties, the Trans Am earned it's heritage. GM and tire makers were coming to grip with radial tires (no pun intended), so the '75 T/A could handle with the best of the on either side of the pond. The buckboard ride associated with Trans Am's, was also lessened, however, this was not without a price as the chassis' sharpness was lessened as well.
Although the Trans Am's price was raised by $294.00 to bring it up to $4740.00, times were good. Record sales of the Trans Am (and Firebird) proved to GM that the decision to pull the plug need not be exercised. Already Ford and Chevrolet were scratching their respective heads, wondering what had the bean counters done. It would not be until 1980 for Chevrolet and 1982 for Ford that a car on par with the Trans Am would serve notice. 27,274 T/A's were built for the 1975 model year, and with the reintroduction of the big motor, the soul had survived.
Now to rekindle the spirit...
Total 455 HO
Total Trans Am
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