The 4.5 by 4.375 is 557(?) inches. A good build with 440-1 heads will make very good torque down low due to smaller ports than the B1. Up to about 800 hp with that many cubes port velocity should make the 440-1 a better choice for a reliable low rpm race motor. You should be able to shift at 6800 with a torqueflite and be in the sweet spot. The B1 will make more power but may need more rpm to do so. I shift my 528 with 440-1` heads at 7200, making 850+ hp.