"How long until it grenades?" Those five words started a string on turbomustangs.com that has lasted more than a year with 50,000 visits and more than 60 pages of replies. Marty Stromberger originally posted it when he decided to find out just how much boost a stock two-bolt Chevy short-block could take. So far, his '88 Firebird has made 703 hp at the wheels and runs 9.74 at 141 mph using the stock block and rotator and a set of iron heads.
The turbo idea was hatched on a road trip from Seattle to Spokane, Washington, when a thought occurred to Marty. The Buick Grand National works with a turbocharger and small-valve heads, so why not try it on a V-8? "I think the Buick is a great idea, but it is too heavy, has a six, and is not very aerodynamic," Marty says. He owned two '84 Turbo Buicks, so he knew that each of those turbos was capable of producing 375 hp each. He did the math and thought there might be a chance to hit 9.99 using two turbos and the right car. The search was on.
Marty's first score was a derelict '83 Firebird SE with a 2.8 and a five-speed from a small car lot for $387. "It drove home billowing blue smoke," Marty remembers. "But it needed everything and it was a V-6 car, so I decided to look for something else." That's when he found an '88 Firebird GTA that had been a weekend warrior/autocross car. It was cleaner than the SE and already had the V-8 parts. "I bought the GTA for $1,500 and a tailgate from a '70 Chevy truck," says Marty. "The car cost a lot more cash, but it belonged to a body man who had fixed all the little things that go wrong with the '80s throwaway cars."
Marty built the entire car himself. He learned his skills rebuilding transmissions at a garage called The Butcher Shop before moving to Tim's Hot Rod Fabrication to work for his father. He stayed there for 15 years, learning to fabricate for the street rod market. During that time, some of the big sellers at Barrett-Jackson came out of the diminutive shop a few miles east of the city. When that shop closed, Marty found a job at Shelley's Automotive, where the Firebird is beaten on its chassis dyno.
Originally, the Firebird was equipped with a 305 and a five-speed combo, with a scrawny catalytic converter welded to a massive Mufflex 4-inch exhaust system. "It sounded cool, but it ran like #@!*," says Marty. So he took the entire car apart and began to prepare it for 9-second travel. "I bought a header kit from Summit Racing and roughed out the exhaust. The A/C and the power steering had to go, but the rest of the power stuff stayed. I wanted to keep as much of it as I could." Under the car, Marty reinforced the subframe and moved the location of the torque-arm mount from the factory bracket on the transmission to the trans crossmember. "GM did that for noise and harshness, but it really should be attached to the crossmember," he says.
Marty knocked out the dings and painted the faded car black, Buick Grand National-style, and dropped in a freshly built four-bolt block with forged pistons, a steel crank, a set of Dart aluminum heads, and the twin GN turbochargers. The engine was on the transbrake at 12 psi when it exploded, taking out a couple of cylinder walls. Marty sleeved the engine and started again. "The repaired engine had a major overheating issue," says Marty. "One day it hit 260 degrees and cracked the deck, relieving the pressure and ending its life."
That's when Marty got his next great idea. The replacement motor had 150,000 miles on it and came from a guy who had been using it in his truck to commute for the last 60,000 miles. Marty was ready to get back to his junkyard roots with a little science experiment: How long until the used engine grenaded? Instead of rebuilding it, Marty just dropped it in including the original 991 truck heads with the 1.72/1.50 valves simply because they were free. "After all, the Buick GN was doing it with 1.71/1.50 valves; why not?" says Marty. That engine made 554 at the wheel on Shelley's Automotive dyno using two bone-stock '87 Grand National turbos that he bought used for $400. The only nonstock parts of the combo were 1.6:1 rockers and a Comp High Energy 268 cam swap. The small cam allowed him to pass emissions and get some tags to drive it on the street. "I got sick of trailer queens," he says.
At the strip the car ran 10.23 at 133 with 20-22 pounds of boost, and then Marty sprayed it with nitrous. "We couldn't kill it; it wouldn't die, so it needed nitrous." Using parts from a carbureted plate system, Marty plumbed a 90-shot about one foot before the throttle body. It made 616 at the wheel and hit 24 pounds of boost. At the track it carried the wheels and ran 9.75 at 141 mph. "What a good feeling," he says.
The combo was working well, so he brought out a set of 487X castings with 1.94/150 valves, changed out the springs, and did a quickie bowl blend before slapping them on the car, just to see what it would do. He pulled the pan and the mains and they looked just the way they did when he dropped the engine in, so he did nothing. By now the guys at turbomustangs.com were following along, and they donated a high-flow Edelbrock manifold base. Then Marty traded labor for a set of used aftermarket TE44 Buick turbos. On the dyno the car made 648 rwhp on the motor and then, with a 75 shot of nitrous, made 703. It also makes 700 lb-ft of torque, "and that's the fun part."