"Rev her oop tae five thousand," said Worm. The Black Tiger snarled in anger and impatience as Randy pressed the accelerator down. Worm put the stethoscope to his ears and the listening apparatus to the carburetor intake pipe. How he could hear anything above the deep roar of the engine Woody could not understand. But Worm was listening as intently as any doctor to the chest of a tuberculous patient. He raised a long finger in the air, and Randy depressed the accelerator further. The Black Tiger's roar was now such that it seemed it must bring down the building. Worm nodded and took off the stethoscope as the roar of the engine died to a quiet purr again.
"It's as I thought," he said. "She's no breathing right around five thousand eight hundred. The air's no ramming through as it should. It's a delicate matter, and I hae me doots whether we can fix it."
"Have to change the contour of the intake and exhaust ports, huh?" asked Randy.
"Aye," said Worm. He saw the mystified look on Woody's face and explained. "It's a matter of using air pulsations tae shoot air through the intake port and suck it oot of the exhaust. I've not got the time tae explain it further. Ye'd find it in Davie if ye ever looked. But it's controlled by the size and contour o' the intake and exhaust ports. It's like using the air as a supercharger for itself."
Woody now began to understand what Worm had meant when he talked about the difference between butchery and surgery in servicing automobiles.
"I'm thinking," Worm said to Randy, "that if the intake ports were polished a bit it might do the trick."
Worm bent over to look. "Somebody installed the wrong gaskets," he said, straightening up. "Yon gaskets are too thick. A sixteenth of an inch will make a difference."
He took the intake manifold off and found two gaskets had been used on them in place of one. Then he took off the exhaust headers and found the same. When they fired up the Black Tiger once more, and Worm listened to her breathing with his stethoscope, he smiled his approval.
"She'll do all right noo," he said.
That, however, was not the end of the evening's, or rather the night's, work. Worm went over every detail of the engine, working slowly but expertly, and Woody's job was mostly to listen and supply cups of hot coffee. He had called up his mother to explain he would be home late, but it was nearly one in the morning before Worm pronounced himself satisfied.