Tiger 428ci (1968), par Myrtle
Myrtle Motors a converti une firebird 1968 et a également été dans le business de "peaufinage" pour le plaisir des clients de PONTIAC, tout comme Royal Pontiac. Bien qu'ils n'aient jamais attiré l'attention autant que Royale Pontiac. Les modifications réalisées par Myrtle à cette Firebird propulsée par un 428ci étaient presque identiques au célèbre kit royal Bobcat (niveau 2). Elle avait le Ram Air, des pneus F70-14. Elle était capable de parcourir le 400mDA en 13.90sec malgré une pertes de traction importante. Il y avait des emblèmes "428" sur le capot, mais pour d'obscur raison également un emblème 400 sur le couvercle du coffre! Un oubli?
Moteur 428ci H.O 390 hp à 5100 rpm et 465 lbs./ft. de couple à 3400 rpm, spécificité de l'arbre à cames d'origine; admission 288 degrés et 302 degrés pour l'échappement. Boite TH-400, 3.90 posi-traction et 12.55sec@110 mph.
Acceleration: 0-30 mph : 3.0 sec, 0-60 mph : 4.9 sec.
Le prix varie de 2781$ à 5149.74$. Myrtl a également modifié des GTO.
Ace Wilson Royal Pontiac, based in Royal Oak Michigan, carried the performance banner for Pontiac. It all began with Pontiac adman Jim Wangers, proposed the idea of dealer-supported performance programs. Pontiac management would allow only one dealer to be a guinea pig, Royal Pontiac was chosen because of convienence. With factory support, Royal Pontiac sucessfully campaigned a 1959 Catalina in NHRA drag racing and then triumphed on Super Duty Monday, Labor Day in 1960, when Super Duty Pontiacs won three major competition events in three different locations. Sales of performance cars and parts escalated from there and Royal Pontiac created the Royal Racing Team for their fans which quickly grew to 55,000 members in just two years. In 1965, Royal mechanics developed the idea of sealing the Tri-Power's three air cleaners in a "pan" that that sandwiched a large foam gasket against the underside of an opened-up hood scoop. This package became an over the counter dealer option from Pontiac in 1965 and debuted as Pontiac's full force Ram Air engine option in February 1966. Along with parts, Royal also offered conversion kits. Early examples included a Paxton-supercharged "Royal Grand Prix" in 1962 (one built) and a hopped-up four cylinder "Tempest Tiger." Then came the first "Royal Bobcat," a big Catalina with all of Pontiac's hotest parts, including a Tri-Power 421, various tuning tricks and tweaks, distinctive paint, and Bobcat identification (made from the "CAT" leters from the Catalina and two "B"s and the "O" from the Bonneville. Royal became the leader in modified Pontiac's and Wangers continued to turn to Royal for all cars prepped for races or the press (including the infamous GTO vs. GTO Motor Trend car - which, by the way, had a 421). At its peak, Royal was selling over 1,000 Bobcat conversions a year, including GTOs, big 2+2s, Bonnevilles, Grand Prixs, and Firebirds. In 1968, Royal started dropping in 428 engines into GTOs and Firebirds, against GM rules, but similar to the shenanigans performed by Don Yenko and others. But in 1969, Ace Wilson decided he had enough and sold his Royal Racing Team to Leader Automotive, run by John DeLorean's brother George. In 1974, Wilson sold his dealership to pursue a land development deal and the Royal era came to an end.
428 Firebird Road Test From Popular Hot Rod, September, 1968 428ci Firebirds were available as dealer-installed options in two places…one in the Midwest – at Royal Pontiac (home of the Bobcat Kit), and the other on the East coast – at Myrtl Motors. Myrtl built 428 Firebirds and GTOs. They sold Tiger supertune kits, traction kits, suspension goodies and anything else in the way of speed equipment to make Pontiacs haul tail. Myrtl Motors allowed anyone to walk in off the street and buy a custom 428 Firebird–tailored to your own specs…adding headers, a Tiger kit, suspension stuff, or even a full blueprinted engine and suspension–in other words, an all-out race car. The test Firebird was painted bright red and had two racing stripes across the functional hood scoops over the top and down the trunk right to the rear spoiler. The stripes and spoiler are on the Myrtl option list. The engine was a not-so-stock ’68 428 H.O. with a few goodies added. Out of the crate, this engine is rated at a strong 390 hp at 5100 rpm and 465 lbs./ft. torque at 3400 rpm. Stock camshaft specs are 288 degrees intake duration and 302 degrees exhaust duration. But we’ve just begun to fight. Now the mind-seizing modifications come in. First of all, take out the stock cam and stuff in a Ram Air stick with 301 degrees of intake duration and 313 of exhaust duration (late conversion will have the late stage II cam). Next, add the heads from a Ram Air 400 engine. These have good valves that won’t burn up after a week of fast running; And a Ram Air induction kit sitting right on top of the engine wouldn’t hurt anything. Now, we put the icing on the cake, add the Myrtl Motors Stage I Tiger kit consisting of cc’d heads to equalize the combustion chambers; special gaskets that block the heat risers and pack more fuel/air charge into the cylinders; special thin head gaskets to raise the 10.75-to-1 compression ratio to about 11.50-to-1; a reworked distributor with a fast advance curve that has the advance all packed in by the time the tach hits two grand; bigger jets for the Quadrajet four-barrel carb; and Isky Poly-Locks on the rockers so that the nuts hold their adjustment when they’re backed off to the limit of their travel. The first blast down the strip smoked the tires so badly we couldn’t even see the starting line through the rear-view mirror. The big inches hauled the Firebird around like a VW. Wesch was right when he said the car was an animal – it did take some getting used to. Making the car very enjoyable to drive was a list of standard factory options that perfectly complemented the 428 big ones under the hood. Things like power steering, power disc brakes, heavy-duty suspension package, 3.90 rear axel ratio with Safe-T-Track limited slip differential, and swing-shifted Turbo Hydra-Matic transmission all made life behind the wheel quite bearable. The suspension, especially, and the automatic transmission made themselves felt all through the test. The suspension consisted of higher rate front coil and multi-leaf rear springs, thicker anti-sway bar up front, and big shocks all around. It kept the Bird on course at all times and provided a very firm, controlled ride. Under hard cornering conditions, the big Bird went into a curve with quite a bit of understeer. But with so much torque on tap, it was no problem to slip the console-mounted control stick of the Turbo down one notch, floor the throttle, and bring out the back end as little or as much as we wanted. After a while, we felt like Dan Gurney at Riverside. It was so easy to make wild cornering moves with the Firebird that we almost thought we were real pro. Never once did the Bird fail to forgive us even if we went in over our heads. All we had to do was back off the throttle, and the rear end would tuck back in. Helping out matters in the handling department was a neat set of Goodyear Speedway Wide Tread tires, size F70-14, mounted on factory optional Rally II wheels with six-inch rims. They’re great as all-around street tires and held up well during our handling tests. But forget it for the acceleration blasts. The Wide Treads just didn’t make it. They just couldn’t hold down the big inches under the hood. We made a few runs with the street tires but couldn’t do any better than a 13.90 ET. This was achieved by simply driving off the line with no torque loading of the transmission. We couldn’t really get into it until we were more than 100 feet out. Things looked keener when we switched to a set of M&H 8.50 X 14 cheaters. The tires had seven-inch-wide treads and a nice soft B-140 rubber compound. They wrinkled up nicely coming off, and we were able to torque-load the Turbo up to stall speed and mash it when the light turned green. Light wheelspin turned into lots of traction, and we recorded times of 13.40, 13.10, 12.85, and finally 12.55. Miles per hour always stayed around 110, and it was just a matter of finding the right off-the-line technique. Granted these times are not the greatest ever turned by a Pontiac. But they’re the best we ever heard of for an unblueprinted Pontiac. If you let the Turbo shift for itself with the stick in Drive, it shrieks into the next gear at 5400 rpm, right at the power peak. Being old four-speed buffs at heart, we had a great time bombing off manual shifts with the auto. We could take the Bird up to six grand, move the stick a notch, the wheels would spin for about 10 feet, and we’d be in the next gear. No muss, no fuss, just right now shifting. Another thing we wouldn’t be without on a car like this is the front disc/rear drum braking system. We ran 10 panic stops in a row, and we were able to stop every time quickly and safely with no swerve or fade. He’ll convince you that the Bird’s the word! List Price (base) $2,781.00 Price as tested (list – includes 428 conversion) $5,149.74 Weight 3,300 pounds 0 to 30 mph – 3.0 seconds 0 to 60 mph – 4.9 seconds Standing start, 1/4 mile 12.55 seconds Miles per hour, 1/4 mile 110 mph Economy 6 – 13 mpg