“I run a throttle-stop that no one else runs,” says Welfringer, who champions the Oldsmobile banner by running Mondello Performance Products out of Paso Robles, California. “I shut the car off at the finish line.”
Welfringer relies on the torque from his 497ci Olds big-block to pull out a big lead over the competition that usually shuts down after the start before racing hard to the finish line.
“This car is a real rush to drive,” he says. “I run from the starting line to the 1,000-foot mark in seven flat, then shut off for around one and a half seconds, then back to wide open throttle to finish. This car goes about 130 at the finish and [his opponents] go 185.”
The Mondello shop works with about 15 racers around the country still sporting Oldsmobile power while most of the business is geared toward restoration and high-performance street builds. The Olds engine in his Brogie-built roadster is based on a stock 455 block fitted with a Bryant billet 4.5-inch stroke crankshaft. It also has MGP 7.250-inch aluminum rods and JE 14.7:1 pistons. On top are Edelbrock heads with 2.150/1.750 stainless steel valves, steel rockers and a stud girdle.
“They don’t flow a lot, around 375 cfm,” says Welfringer, who has worked at Mondello since the late ’90s and now owns the operation following the passing of the legendary Joe Mondello, also known as Dr. Oldsmobile. “Which is the reason the motor doesn’t have a lot of rpm. It’s got about 785 horsepower but never exceeds 6,500 rpm.”
The cam is a 4-7 swap design from Crane that provides around .800-inch lift. Induction is through a Book 1250 cfm alcohol carb into an Edelbrock Victor intake manifold.
“The only reason I run methanol is that it’s easy on the engine by keeping cooling temps around 145,” adds Welfringer. “This motor never gets warm.”
Welfringer says he leaves the starting line at 5,500 rpm and shifts one second into the run.
“I run the motor soft because it makes so much torque and you can shift early,” he explains, noting that the torque curve flattens out and stays at 5,000 rpm. “The car has real efficient 60-foot numbers. I tried 16:1 compression but the motor was so explosive in the middle of the track. What we’ve done is to try and corral all that torque.”