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Heads would need to match the IM, wiring harness and ECU. If the EJ22 is single exhaust port, then you'll need the matching exhaust manifold as well.
 

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opendeck251+stiInternals
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EJ22 heads on EJ25D block makes the high compression motor, meaning you have to run premium fuel. You need the EJ22 intake manifold to match the heads, and you need to swap over the EJ25D's intake manifold wiring harness onto the EJ22 intake manifold.

If this sounds like too much work for you, you can just swap in a complete EJ22 longblock and call it a day. As jton said, the 90-95-ish EJ22's had the dual port, the 97-01's has single port exhaust header, you can just swap on whichever one you need to and it will be fine.


~Josh~
 

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Would it be any interference between the 2.5 DOHC heads and the EJ22 block? I've bought a 98 EJ22 for my 98 forester, but now I need to either find a single port exhaust or swap the heads. Main issues would be piston to valve clearance. Any ideas ?
 

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Not unless the timing is set wrong. Yes it's true the EJ22 pistons protrude above the deck by .010" or so (can't remember the exact number) but the headgasket is .050" thick. The valves don't protrude below the head deck IIRC, unless you have had the head severely decked. Even then I don't think they do. The pistons have pockets designed to add clearance for the valves, however the factory cam profiles don't open soon enough or close late enough to cause valve-piston contact, even between heads. And I don't believe its on the edge either, you can buy regrinds which are more aggressively profiled. If you went aftermarket, then I'd say you should check clearances. But stock? Not an issue.
 

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opendeck251+stiInternals
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I will say this one more time.....

You can put ANY EJ head on ANY EJ block, period. As long as you use the headgasket that was designed for the block, you won't have issues.

End of story. Now let your mind ponder all the engine combos you could make.


~Josh~
 
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