im thinking it would work the other way around or with some awkward configuration of parts I didnt try yet. 

 

Works on an EA81 in an EA82 body car with EA82 radiator.

I attempted it on an ea81 in an ea81 car w a ea82t rad. pulleys didna line up. do you swap the harmonic balancer too? i didnt try that way

Well. I finally got some time and got my subaru running...sort of. I used ea81 engine. Had heads done at machine shop. Install new rings. Installed ea82 manifold. Welded shut the little coolant port by carb. Removed egr and plated. Removed the things that bring air into exhaust just off heads. Removed catalytic converter. Added new weber carb. Mated it up to five speed with ea81 flywheel and pressure plate and clutch from ea82. I tried to use ea82 water pump as suggested here to make coolant lines easier to run to ea82 radiator, but couldn't as pulleys don't line up. Used ea82 coil with a long lead. . It's pretty clean. That's what I wanted.

 

Now for the problem. It fires up with about half throttle. Runs pretty darn smooth at about 2500. Doesn't smoke. Good oil pressure. Good temp. Will not idle. Runs rough up to about 1500 before it smoothes out. At "idle" with foot on throttle just enough to keep it going it sounds like on old John Deere. And its rough. Almost like its fighting itself a little. Timing is set about 9 btdc. No amount of idle speed or mixture screw adjustment changes anything.

 

Any ideas would be very much appreciated.

check the coolant temp sensor. plus if you closed the coolant port to the base of the carb its going to ice up and cease to function

I had a similar problem, I checked every thing I could think of then my Girlfriend asked me if I checked the fuses......Thanks babe.