Learn me: Subaru Frankenmotor

Less in general than more specifics of what I need.
The biggest ingredient is the 2.5 short block.
Does it have to be an early one?
The internet recommends an EJ25D block as ideal, but doesn't tell me if there's a cutoff after which newer blocks won't work.

FWIW I've got the original 2.2 out of the legacy, don't want to put it back in without making it better plus adding a five speed behind it.
The rest of my plans for this car have failed miserably, trying to salvage something from it.

Going for a normally aspirated setup? EJ251 shortblock will work fine, reuse your early EJ22 heads, intake, exhaust etc. 251 head gaskets, 22 timing belt. It'll likely want 91+ octane, but should be a hell of a good time.

If you want boost, I'd just freshen up the existing EJ22 and jam on a snail.

No boost, gave up on that dream when I was unable to find the missing parts for the TT engine I bought last year.

Still murky, I can or cannot use any Subaru 2.5 block?
Some parts of the internet say only 'early' 2.5's, others imply any.

So the internets say, any 2.5 will do. I'm not sure there's any good reason not to go with a twin cam D block, they're available on every street corner for $0.80CAD and a pack of Sweet Tarts since eveyone thinks they're cursed. Rule of thumb is just match the headgaskets to the block, timing belt to the heads.

Thanks!
Despite being in the heart of Subaru country, I've been having trouble sourcing ANY 2.5 block locally, much less a particular one being recommended.

In reply to SnowMongoose:

If you want to go turbo I have: exhaust manifolds, up pipe, turbo, intercooler, and wastegate from a forester xt. I would give you for shipping. Of course all that cast iron may be a bit expensive to ship.

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I confused myself with 2.2L Phase 1 and Phase 2 motors and how they match to the 2.5 blocks.

you are much better off doing the full 2.5 swap. the hybrid is mostly a junkyard build for people that want to make something cheap. nasioc has a million page thread dedicated to this build but they also seem to blow up at a high rate: is it junkyard parts or the crazy compression ratio some are quoting? easiest thing on the ej22 is a set of cams... then you go straight to pistons and big valves.

In reply to HFmaxi:

This car has been sitting at my buddy's shop for far too long, I'm looking for a route that gets it back on the road quickly.
This seems to be the best compromise between speed and not just slapping the quarter million mile 2.2 back in.

put in a 100k mile 2.2? you'd still be using the quarter million mile heads. to answer the question: you can use the ej25d ej251 or ej253 so the dual and single cam N/A 2.5s of the late 90's early 2000's. others might work as well. but a complete 2.5 long block would be the easiest

A modern EJ25 will need piston clearancing to work with a late 90's head. My buddy went through this after he spun a bearing in his Impreza RS.