This surely could not be a coincidence the two series are aligning their design philosophies?
Also, this from
http://www.indycar.com/
Engine basics
Capacity – 2.2 liter maximum
Cylinders – Up to six, all of equal capacity
RPM – 12,000 as restricted by the Engine Control Unit
Horsepower – Between 550 and 700 dependent on type of circuit
Fuel – E85; fuel injection allowed
Fuel capacity – 18.5 U.S. gallons
Oil – Can use only lubricating oil that is readily available to the general public through retail methods
Boost pressure – 155KPa for road courses, 140KPa for short ovals and 130KPa for speedways. Two boost sensors will be fitted and monitored by INDYCAR
Minimum weight – 112.5kg (248 pounds) excluding items such as the clutch, ECU, fluids, turbo charger
Turbocharged – Single or twin featuring water-cooled bearing housing and titanium turbine wheel
Mounting – Common mounting points on bulkhead and gearbox for all three manufacturers
Engine life – 1,850 miles. Each full-season entrant will receive five fresh engines per year
“Push to Pass” – Not to start season
KERS – No
Pop-off valve – No
Traction control -- No
Anti-stall -- Yes
Engine architecture
Bank Angle – V6 engines - between 60 and 90 degrees
Bore – V6 engines - 95mm diameter maximum
Engine length – V6 - 460mm, measured from mounting face to mounting face
Crankshaft height – 100mm above bottom of chassis (lowest point of sump)
One piece crankshaft – homogenous with no additional non-ferrous inserts or bolt-on balance weights
Main bearing minimum dimension – 48mm diameter
Big end journal minimum dimension – 40mm diameter
Connecting rods – Homogenous, no welding or bonding
Piston pin – single piece only
Valve type – Reciprocating circular poppet, return force via coil spring only
Spark plug – One per cylinder otherwise free
Coatings – DLC coatings are not permitted on crankshafts, rods, camshafts, piston skirts or sleeves.
Camshafts – Up to four overhead camshafts permitted (2 per bank)