The " - " is a dome. When you figure compression ratios, a negative is actualy the amount of cc it is displacing in the bore so to speak. Negative is a dome, positive is a flat top with reliefs. The relief would be a valve pocket/s.

Theoretical C/R because the 2295 is a 2.029 C/H piston:

# of Cyl. 8
Bore 4.3200
Stroke 3.7500
Rod Len. 6.760
Gskt Bore 4.490
Comp. Gskt .0400
Block Deck Ht. 10.7200
Top ring down 0.280
Chamb. Vol. 88.0
Dome (-) Dish -12.00
Piston / deck 0.000

Total volume 988.49
Cylinder volume 900.72
Clearance volume 87.77
Gasket volume 10.38
Top ring volume 1.39
Deck volume 0.00
Piston top land 4.275
1/2 Stroke 1.875
Comp. Ht. 2.085
Cubic Inches 439.72
Compression ratio 11.26

Now lets do it at the 2.029 ( .051 in the hole):

# of Cyl. 8
Bore 4.3200
Stroke 3.7500
Rod Len. 6.768
Gskt Bore 4.490
Comp. Gskt .0400
Block Deck Ht. 10.7200
Top ring down 0.280
Chamb. Vol. 88.0
Dome (-) Dish (+) -12.00
Piston / deck 0.051

Total volume 1000.74
Cylinder volume 900.72
Clearance volume100.02
Gasket volume 10.38
Top ring volume 1.39
Deck volume 12.25
Piston top land 4.275
1/2 Stroke 1.875
Comp. Ht. 2.026
Cubic Inches 439.72
Compression ratio 10.01