Been considering swapping my ej255 engine in my wrx to either a ej257 or ej207. But i have been having troubles locating a ej257 without a ridiculous price tag associated with it, iv seen alot of people swaping just a ej257 shortblock and keeping the wrx heads and using a thicker headgasket with arp headstuds, with different degrees of success. I was wondering if i got my hands on a ecu and engine loom from a ej20 model (wrx or sti) and swapped in a v7/v8 207 which cost alot less, would it be that much of a pain to swap in over the current ej255?

I have a friend who is mid way through putting a v7 sti moter into his 02 wrx so i would be looking todo this myself with his help.

Putting a 207 in a car that originally had a 255/7 in is going to be a headache and will require an aftermarket ECU.

The 2.5 heads dont physically fit as they are too big for the 92mm bores on the 207 shortblock. So then you're looking at swapping heads over which brings its own problems. The 2.5 heads use different sensors and the cams have different trigger patterns.

That's not to say it cant be done but it's complicated.

Also judging by what you've written you need to do a bit more research. Your combinations are all over the place. The swapping short blocks and thicker gaskets thing is for people putting in a 2.5 short motor using 2.0L heads. You're wanting to put 2.5 heads onto a 2.0L short block which cant be done because the physical size of the chamber on the heads is bigger than the 92mm bore of the block.

If I were you i'd either rebuild what you have or just buy a EJ257 short motor.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

Thanks for your reply,

With buying a EJ257 short motor, is there anything i would need to do to insure reliability of the engine(257 bottom with 255 head) because i believe there is a slight change in compression from the stock 255 long block.

Will be hard to beat these prices on new short blocks.

- Engine Packages
Rising Sun do oem short blocks cheap too.


You could try and bargain with Subaru locally, they had three brand new 257 short blocks sitting on the shelf in Welshpool last week but they want $3400 each.

I believe if you have a quote they will try and price match, might be worth a try.

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Bye bye betty blue. Hello F6.

I'm using EJ255 heads on mine.

As long as power levels are kept sensible and it's tuned properly you shouldn't have problems. Three things I'd suggest: New oil pump, RCM head gaskets and some arp2000 headstuds.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

The only difference between an ej255 and new ej257 short block is the compression ratio and the ej257 comes with a head treated crankshaft. Block casings, rods are exactly the same. Ej257 isnt semi-forged like the ej207 if that is what you are hoping to achieve.

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The one perkent...

Whats a semi-Forged?

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Doing it for all the wagons out there

The nick name people give the factory forgies in v7 207

using the Perth-WRX mobile app

Tony gives me a semi.

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Bye bye betty blue. Hello F6.

Thanks a lot, i guess a ej257 short block is what i will do then. And how sensible will i have to keep the power levels?