a lifelong engine builder i know raced his well built 340 duster to best of 11.47.Stroked it to 372 changing absolutely nothing else it ran 10.47.Edelbrock heads,4.88 gears shifting at 7800.It wasn't long before he cracked a cylinder.
That brings up an important point about stock blocks. The cylinders were made for 275 HP or so, then we go and thin them by boring them out.
NHRA just allowed the aluminum race 6.1 block to be used in the 6.1 DragPak stock class cars because factory iron is almost non existent anymore. Horsepower went up dramatically with that change in my friends car.
