I have a 03 Baja and am replacing the EJ25 engine in it. I was looking at one that is an EJ25D. Will that work?

No. 25d is a DOHC engine. Only 96-99. Too many differences to make that work.

 

You need a 251 SOHC. 00-04 legacy or 99-04 Forester. Put your original intake manifold on the new engine.

Actually 03 is going to have EGR (unless the baja is wildly different from the legacy/outback). The engine block is the same as 00-04, but the heads are 03 only because 04 has the oval exhaust ports.

Your best bet is to get an 00-04 engine block and bolt your heads onto it. Whatever used engine you get you're going to want to replace the head gaskets anyway, it would be insane not to. So just save yourself the trouble of finding an 03 and re-use your heads.

Edited December 30, 201411 yr by 987687

i've done it before, you can use an EJ25D but you need to use thick headgaskets - the pistons protrude past the block and can strike the heads if you use a really thin headgasket.  i forget which gasket i ended up using but i'm sure it woudlnt' be hard to figure out.

 

not too mention the EJ25D is the worst engine subaru ever made.  very high chance that a used EJ25D has been overheated before - and when they overheat - it is completely random, can be separated by months between incidents, come and go - and lend themselves to people liming them around for too long/too many times overheating...then they can get misdiagnosed many times...mechanic replaces radiator (i have one in my driveway right now - bad headgasket - mechanic replaced radiator 4 months ago...it's the headgaskets), then thermostat...more overheats in between....anway - they're just a risky engine.

 

i'd get a SOHC Phase II block. that being said i have a known good EJ25D block that has a high likely hood of having never been overheated if I can't get it to a guy in California who wants it:  $400.