Ported Indy VS open chamber ported W2

How Much would you benefit with Indy heads Vs W2 both ported with same components besides the weight?

That depends on the level of porting done. If the same person was doing the work, or lets say a full port W2 vs. a cnc 230 ported Indy oval port head...IF the engine was large enough and has enough compression/cam, etc.. the Indy will make more power.
The 230 port is pretty large and would take a ton of porting on a W2 to match...might be impossible within the W2 casting.

It would really depend on the engine and what it needs to get the job done. A typical RHS headed street 410 will make 480-520HP on pump gas while a 420cid sb with 13:1, race gas, large roller cam and rpm ceiling of 7500rpm will make over 700HP with an Indy head.
Brian