Here is some info I found:
2004 Hemi specs:
Compression Ratio 9.6:1
Combustion chamber volume 84.9cc
Intake valve angle 18 degrees
Intake valve head diameter 50.8mm, 2.00 inches
Intake valve lift: 0.472
Exhaust valve angle 16y.5 degrees
Exhaust valve head diameter 39.4mm, 1.55 inches
Exhaust valve lift: 0.460
Valvesprings: Conical, 97 pounds closed, 242 pounds @ max lift
The 2 inch ports flow 270 cfm at .600 inches of lift, with peak flow at .375 inches. At .250, the stock head also had excellent flow. The exhaust port hits 161 cfm at .600 lift, with a 1.55 inch valve.
The 2009 Hemi brought variable cam timing; a higher compression ratio; higher-flowing heads, intake, and exhaust; and an active intake manifold that switches from long runners to short runners, to optimize the engine for either better high-end horsepower or better low-end torque. Other upgrades are crankshaft structural upgrades, a dual-mass crankshaft damper, floating pin piston design, valve spring design, and oil pump capacity increase.
Cylinder heads. Big changes here, new closed chamber heads have smaller chambers than previous engines , 66.3cc in fact vs 84.9cc. Even smaller than the 6.1's with 73.0cc. Bolting these on to a previous Hemi without modification would result in nearly a 12:1 compression ratio. Valves are slightly larger. Intake is 2.05" vs 2.00". Exhaust is the same. Both valves have a longer stem though. New bee hive valve springs, identical on both intake and exhaust are now in use, and seem to mimic what some have been doing in using the 6.1 exhaust springs across all valves. Pushrods have changed as well, they are now approximately 4mm longer, putting them very close in length to the 6.1's pushrods. Ports appear to have a 6.1 sized window on the intake side, as well as a 6.1 style D shape on the exhaust. A quick comparison with a 6.1 exhaust manifold looks like it was nearly a perfect match.
Active intake manifold on the 2009 and up Rams: