Here are the stats, straight from the FPV site.
The way these stat read (and being Ford, they must know their product better than anyone else), the Boss motor is, in fact a very good motor and doesn't actually need to rev above 6000rpm.
The block is cast-iron which makes it exceptionally rigid. It is three times stronger than aluminium for extra durability reserves and refinement under high horsepower and torque loads and maintains tolerances better. Cast-iron is more stable over a wider range of temperatures and there is less movement at critical sealing points for superior resistance to oil and coolant leaks. Ultimately, it's what we use for V8 Supercar engines. Enough said.
The engine has an under-square bore and stroke ratio that delivers the flexibility, fast response and strong pulling power from low engine speeds expected from a high-performance V8.
A forged steel crankshaft maintains strength and refinement under high power and torque loads.
Each crankshaft undergoes a special balancing process at Ford Performance Vehicles prior to assembly to match the special Boss 290 piston and conrod combination for exceptional refinement and reduced stress on components at all engine speeds.
Locally-sourced high-performance tri-metal main and big-end bearings are specified for extra durability under higher engine speeds and peak power and torque loads.
Each main bearing cap is precisely located by two cross-bolts, two vertical bolts and two vertical locating dowels for superior location over six bolts. That means superior durability and refinement under high performance loads.
Each conrod is re-engineered to match the stronger pistons and floating gudgeons.
The conrod big-ends are separated by a controlled cracking process before main bearing insertion. When reconnected, this creates a multi-ridged join unique to each conrod that is exceptionally strong and virtually invisible.
Locally-supplied high-performance pistons with domed tops lift the compression ratio to 10.5:1 on 96 RON PULP for improved engine response, efficiency and fuel economy under light throttle loads.
The oil pump is driven directly off the crankshaft. So when the engine is running, the oil pump is too. And that eliminates one serious potential for engine failure (for example, when a separate oil pump drive breaks and the engine continues to run).
Extra components are;
FPV Hi Comp pistons and Piston ring pack
FPV Re-engineered Conrods with fully floating Gudgeon pin (assume XR8 Boss 260 doesn't have these)
FPV High lift Inlet camshaft (13mm lift), Outlet (12mm lift)
FPV Valves, Valve Springs, Finger Followers, Balanced Camshaft, Heavy duty bearings, Hi Flow Air Intake System, Long Runner Intake Manifold, Stainless steel Exh manifolds, Hi Cap fuel pump.
Is this 'hardening' or just sale gumpf? I read it as hardening and it is an exceptional motor. Over and above that, Ford Aust told the press the Cobra motor was made from rudementry rough castings that lasted only 3000 times then had to be thrown away (because of poor quality?), and the FPV product was well above that in quality.
The only confusing thing above- how many bolts does the big end actually have - 2, 4 , 6 8 or 12, if dowels are counted as 'bolts'. Even taking 'dowels' out of the calculation, the way it reads is 10 bolt mains. Haven't seen these used - heard of 2 bolt, 4 bolt.