The fast version of the It/CA/1931 design is a modest improvement

The main improvements in the It/CA/1931 "Fast Version" over the 1929 design is a knot more speed (36 knots) and a somewhat better AA armament. The main armament is still 8-8in guns, but there are now 8-4in and 24-37mm AA guns. The belt is 3in and the deck is 2in. This is the Springsharp report:

It/CA/1931, Italy Heavy Cruiser laid down 1931 (Engine 1945)

Displacement:
 13,466 t light; 13,920 t standard; 14,600 t normal; 15,144 t full load

Dimensions: Length overall / water x beam x draught
 651.57 ft / 650.00 ft x 67.00 ft x 21.00 ft (normal load)
 198.60 m / 198.12 m x 20.42 m  x 6.40 m

Armament:
      8 - 8.00" / 203 mm guns (4x2 guns), 256.00lbs / 116.12kg shells, 1931 Model
   Breech loading guns in turrets (on barbettes)
   on centreline, all forward, 2 raised mounts - superfiring
      8 - 4.00" / 102 mm guns (4x2 guns), 32.00lbs / 14.51kg shells, 1931 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, all amidships
      24 - 1.46" / 37.0 mm guns (12x2 guns), 1.55lbs / 0.70kg shells, 1931 Model
   Anti-aircraft guns in deck mounts 
   on side, all amidships, all raised mounts - superfiring
 Weight of broadside 2,341 lbs / 1,062 kg
 Shells per gun, main battery: 120
 8 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 3.00" / 76 mm 420.00 ft / 128.02 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 99 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 420.00 ft / 128.02 m 21.00 ft / 6.40 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 4.00" / 102 mm 3.00" / 76 mm  4.00" / 102 mm
 2nd: 1.00" / 25 mm       -   1.00" / 25 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 172,081 shp / 128,373 Kw = 36.00 kts
 Range 4,500nm at 15.00 kts
 Bunker at max displacement = 1,223 tons

Complement:
 663 - 863

Cost:
 £5.784 million / $23.136 million

Distribution of weights at normal displacement:
 Armament: 293 tons, 2.0 %
 Armour: 2,717 tons, 18.6 %
    - Belts: 633 tons, 4.3 %
    - Torpedo bulkhead: 326 tons, 2.2 %
    - Armament: 572 tons, 3.9 %
    - Armour Deck: 1,134 tons, 7.8 %
    - Conning Tower: 51 tons, 0.4 %
 Machinery: 4,345 tons, 29.8 %
 Hull, fittings & equipment: 6,111 tons, 41.9 %
 Fuel, ammunition & stores: 1,134 tons, 7.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   15,543 lbs / 7,050 Kg = 60.7 x 8.0 " / 203 mm shells or 2.0 torpedoes
 Stability (Unstable if below 1.00): 1.16
 Metacentric height 3.6 ft / 1.1 m
 Roll period: 14.8 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.50
 Seaboat quality  (Average = 1.00): 1.04

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.559
 Length to Beam Ratio: 9.70 : 1
 'Natural speed' for length: 25.50 kts
 Power going to wave formation at top speed: 62 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 3.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  30.00 ft / 9.14 m
    - Forecastle (20 %): 29.00 ft / 8.84 m
    - Mid (50 %):  29.00 ft / 8.84 m (21.00 ft / 6.40 m aft of break)
    - Quarterdeck (15 %): 21.00 ft / 6.40 m
    - Stern:  21.00 ft / 6.40 m
    - Average freeboard: 25.08 ft / 7.64 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 159.6 %
  - Above water (accommodation/working, high = better): 189.9 %
 Waterplane Area: 30,643 Square feet or 2,847 Square metres
 Displacement factor (Displacement / loading): 106 %
 Structure weight / hull surface area: 119 lbs/sq ft or 582 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.74
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent