I have a 2006 Outback Auto with an SOHC  EJ25 NA (Naturally Asperated) motor with the Active Valve Control.  It threw a rod right through the block.  I want to buy a JDM SOHC EJ20 NA motor and use the heads (and Intake manifold) from the blown motor.  Has anyone done this? Will it work?  I checked on Rock auto and the head gaskets seem to be the same from 2000 to 2009 and I seem to have heard people saying all SOHC EJ will swap heads.  I guess one of my concerns is what compression ratio I will end up with.  I know I will loose 500cc but I dont think that is the end of the world, especially on an AVC car.    Than you. for taking the time to read this. and any input is always appreciated.

Your engine has avls, not avcs. The na ej valve timing system has jack to do with performance, only changes to a small cam lobe at idle and extremely low load to reduce emissions. 

 

Onto the heads. Yes, they will physically bolt onto the ej20 shortblock, the head gaskets are not the same between the two however. The head gasket is the same for all of the ej25 sohc engines from 00-09, not for all sohc ej's the world over. Itis also a bad idea to do those heads, which have a roughly 99mm wide combustion chamber, on an ej20 block with a 92mm bore. You'll have massive combustion chamber overhang which will be a prime place for hotspots causing pre-ignition, and very little cylinder wall for the head gasket to seal to. 

Edited September 19, 20196 yr by 86BRATMAN

i have used the earlier DOHC 2.5 short blocks and their corresponding head gaskets. You can still buy these thru JDM importers.

 

Ok. Understood. I think I will just have the to find a ej25 SOHC short block and put on the heads. That is if they are still ok.