Ford Big Block 521 Head: Kaase P51 Bore: 4.390
- Bore: 4.390"
- Stroke: 4.300"
- Rod Length: 6.800"
- Compression Height: 1.350"
- Dome: Flat Top
- Dome/Dish Volume: -7.6cc
- Reference Chamber: 72.0cc
- Catalog Compression Ratio: 12.40:1
- Piston Weight: 614g
- Resulting Displacement: 521 cid