Dave Gimmarro / Wayne, MI On a whirlwind tour of several shops in Detroit recently, we stopped in at Don Walsh Jr.’s dyno shop behind D&D Performance in Wixom, Michigan. Don Jr. has built a reputation both as a five-time NMRA Pro 5.0 champion and as an excellent tuner. The day we were there, he had Dave Gimmarro’s supercharged small-block Mustang on the rollers, trimming the air/fuel ratio and timing in preparation for some serious 7-second action. On this first test, as often happens, they learned what didn’t work—if you can call making “only” 1,262 rwhp a disappointment. Don says, “We basically ran out of fuel pump. We learned [with our race car] that when you have a 1:1 regulator, a base fuel pressure of 80 psi, and 40 psi of boost pressure, the demand on the pump is well over 100 psi. That’s when the capacity really drops off.” He says the solution for his Pro 5.0 car was to convert to a mechanical fuel pump that could easily accommodate both the higher pressures and the volume requirements. In a later interview, Dave told us he had just received a Waterman Mini-Bertha pump in the mail, and it won’t take long to get the pump— rated at 12.5 gallons per minute—cranking. That’s like using a fire hose pump, as the Waterman has the capacity to crank out more than 4,800 pounds of fuel per hour. Don says that with a high capacity mechanical pump, he’s able to make loads of horsepower even with smaller 165 lb/hr Bosch injectors. “I’ve got it on cruise control right now. There’s a lot left in it.” Don Walsh Jr. on the Ford small-block’s tune-up “That blower won a championship for us. It’s six years old . . . it’s my favorite piece.” Don Walsh Jr. on the Procharger F3 supercharger on Dave’s Mustang It takes a stout transmission to handle this kind of power. Starting with a 10-inch Neal Chance aluminum bolt-together converter, the power surges through a Rossler two-speed ’Glide on its way to a 4.88-geared 9-inch. The Mustang pushes all this power through a set of 31-inch-tall Mickey Thompson drag radials. Dave’s wife bought this ’88 Mustang LX way back in 1990 complete with a 5.0 and an automatic. It eventually became a 10-second street/strip car before its transformation to full-on race car that has taken about six years to complete. How quick? “I guess you could say I’m shooting for low 7s,” Dave says. As one wag put it, “That’s got to be like driving a Fuel Altered on drag radials!” The Procharger F3 supercharger dominates the engine compartment, even with the front clip removed. With a 112mm inlet, Don Walsh says on this particular day he was pushing about 31 psi from the supercharger. According to Procharger, the F3 is capable of more than 40 psi and can move around 3,100 cfm of air. That, friends, is equivalent to a small hurricane shoving air into an engine. What’s on top includes a Ford Motorsports single-plane intake using a 105mm Wilson throttle-body. The manifold is stuffed with 165 lb/hr Bosch injectors controlled by a BigStuff3 EFI electronics package. The small-block swills VP C16 fuel with a motor octane rating of 117. What you can’t see buried under the centrally located blower and inlet system is a custom Dart iron block using an intermediate 8.70-inch deck that’s in between the 5.0L engine’s 8.2-inch height and the 351W engine’s 9.60-inch height. The short-block includes a Sonny Bryant steel crank and Diamond 8.8:1-compression pistons. The Yates heads are fitted with large-by-huge valves driven by a mechanical Comp cam that pushes the valve open “into the high 700s,” Dave says. By Jeff Smith Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!