Anyone know what the size differences are b/n SOHC 2.5 heads and those of the DOHC heads? A link to some page would be helpful. I'd like to keep my SOHC heads, but I'm wondering about a 2.2L turbo block. However, I don't want to bolt on those heads and get a 7:1 compression block.

SOHC heads yeild approx 7.6:1 compression.

Thank you :). 7.5:1-ish is very acceptable. What does it do to the squish area? Does the piston crown still line up nicely with the head?

The squish is not exactly ideal, but it's not horrible either. I recommend that you use the SOHC 2000 2.2 headgasket. Part number is 11044AA542. I have run 30 PSI on this setup at altitude from a t3/t04e with no problems. 12.4@107 at 4800 ft above sea level with a slipping clutch and basically untuned.

Hmmm....keeps looking more promising. Did you upgrade your valve springs and o-ring the block, Drac? I'm looking at stock ECU + J&S for timing retard, and a set of secondary injectors. Weren't you running a link, too? Details, man, details! ;). My goal is eventually 30psi of s/c boost, and I KNOW it can be done on factory parts with a bit of machined help. The 2.2 turbo motor is just rock solid. Trannies are another issue...........

now, is that with the 2.2 turbo pistons or the n/a pistons?
if that's with the 2.2 turbo pistons then that means I could still be in a safe range if I put them on my n/a piston engine.

It's the 2.2 turbo block from an older turbo legecy. It's not the same as a 2.2 n/a engine at all. It's the factory turbo block (tough as nails.).

I knwo that the EJ22G is different than the EJ22E, but, my question was simply was the block with the 2.2 turbo pistons or was that with 2.2 n/a pistons. but I have that answered.

I am running a completly factory longblock. The heads are stock springs and retainers (for now) The bearings, rings, gaskets, etc are all factory parts. I have not o-ringed my block or heads. The block had 130k on it when I got it from the junkyard. I put it in the back of my wagon and drove it straight to the machine shop. The block still had the crosshatching on the cylinder walls. It was just honed out, and all stock parts used. I even made 19 12 second passes on the stock tranny in one night :) The exedy clutch didn't like that though. :)

And yes, I am running a link plus.

http://wac.addr.com/auto/obs/turbo/ejcalcs.html

this has all the info I would really need. though i'd post it because it's good information.

yeah i've been told that my 2002 rs sohc heads on my ej22t block give me mid 7:1 cr. from wut i've read there's a ring that you hafta deal with when u mate the rs heads to the the legacy block but it doesn't really hurt anything initially. u can hav it machined and from wut i understand stock rs heads flow much better than even worked legacy turbo heads. its a good setup, and it has even more potentil down the line. goodluck dude.

IIRC, the DOHC heads have 47cc and the SOHC have 49CC. There are a number of mistakes on that E-calcs site Jonofscio linked. And damnit, quit calling the EJ22T USDM Legacy Turbo engine the EJ22G. Do I need to post a picture of my fricking engine bay to convince you that you are totally wrong about that designation. Continuing to spread that sort of misinformation is part of why it took me nearly a year to convince people that the 22B and the USDM Legacy Turbos don't share the same block!

And yes, you can put the Legacy Turbo pistons into your EJ22E to drop the CR, but why bother. If you use SOHC EJ25 heads on your stock block it runs a very safe 8.6:1 CR. Cracking open a Subaru block to change pistons is a PITA, and the difference between the two CR's is such that with one you could run up to mid teens boost and the other you could run 11 or 12 without blowing up your EJ22E block...

Hamfist
Either the SOHC or the DOHC heads will be a good match for an EJ22T block. That slight difference in CR is pretty neglible and there are plenty of guys around who have done it both ways.
Drac9
Xephyr
HOK
Wedge
JC
No-Coast-Punk
etc. etc...

hey, I thought the usdm legacy turbo motor was an EJ22G. I know it wouldn't say that on the block, but the vin/engine/color code/trans plate would say so.

and I know that the 22B engine is not the same as the usdm legacy turbo motor.