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Guest Message by DevFuse

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Engine Swap info

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2 replies to this topic

#1 Uncle Ed

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Posted 14 February 2010 - 11:54 PM

This information was saved from the Prosubaru web site, and was saved in printed form. The site is no longer on the web! If this information isn't wanted or accurate then please delete.

Engine Swap Information

Here is the largest collection of engine swap information available on the internet. Article came from countless hours in the scrap yard, measurements, attempts, and various internet sources. I hope you find something useful, there is a lot of information here!!!


Get a complete engine pull and take pics of your car and the donor before starting. It is also a good idea to label all wiring and hoses on both engines.

All subaru EA-Engines can replace each other with little or no modifications!

Subaru EJ-Engines can replace most EA-Engines beginning in 1977!

All Subaru EJ- engines can replace each other with electrical modifications!

The EA71 will replace all EA61/EA63 engines with no mods. Heads will swap in pairs.

The Ea71 Heads will directly replace the EA81. Even though the EA 71 block is 1” shorter the heads will swap in pairs and raise your compression ratio to 9:1, (higher with EA71 pistons).

The EA81 will replace many EA-Engines, and is a direct replacement for 84-
87 EA71.

Your MUST use the clutch disc and bearings that match your original transmission, along with the pressure plate and flywheel to match the repacement engine. Occasionally you will run into bellhousing and starter issues, this is because the Subaru used four different bellhousings and three different basic starters. Here is the breakdown simplified as much as possible:

Narrow Housing

ID: The early, or narrow housing is extremely narrow and has a 12 O'Clock top
Mount starter. This housing will not fit any oter engines but fits all top starter [indent=1]]transmissions.

Use: EA52/61/62/63 Engines. Terminated in 1974.

Wide Housing

ID: The wide housing is identical to the early unit but is 2” wider, 12 O'clock top
mount starter. This housing will fit all EA63 & 76-83 EA 71 engines and all
top starter transmissions.

Use: Used on late '74 and all '75 EA63 and most EA71 until terminated in 1984.

EA Housing

ID: This housing is identical to the wide housing but has a 10 o'clock side mount [indent=1]starters. This housing will only fit 84-87 EA71, all EA81/82, and all side
start EA- transmissions.

Use: Used on 84-87 EA71, all EA81, all EA82 and all ER27. Terminated in 1994.

EJ Housing

ID: This housing is similiar to the EA housing, but is 1/2” Deeper and two top
studs are slightly off center from the EA Housing. Most Starters are still
mounted at 10 o'clock, but some are in other places for space saving. These
[indent=1]are still interchangeable with all current combinations.

Use: Still in use today with all EJ engines , EG33, and EZ30/36.


All EA 52-62 use the same starter, not interchangeable with anything except narrow housing EA63. Wide housing EA63 thru EA82 use the same starter. The EA82T and ER 27 use the same starter, it is just higher powered and can be bolted-on with no problems. EJ/EG/EZ starters have a different drive end than the older units, but are all similar coming in different shapes & sizes to save space. Turbo starters are once again stronger and interchangeable. Some early FWD used the EA-drive end, making starter swap possible, even onto new engines simply by attaching the new drive end to an older starter... cool, isn't it?

Now that you're up to speed on subaru swaps, you may proceed to the nitty-gritty swap information. Hopefully this will serve as a guideline to aid you in your swap decision and save you a few hours in doing it... Enjoy!

Swapping an EA61 to an EA63:

All EA61 and EA63 engines are 100% bolt-in swaps. In fact, they share most every part. Reuse your original intake, carburetor, and distributor. Some 74-75 EA63 used the wider EA71 bellhousing, so you might want to snag that starter too, just in case. Clutches and Pressure plates are identical. An evening job!

EA62 Swaps:

The EA62 found in the 1300G has rear exhaust ports (like a Type 1 VW). It can replace EA61/EA63 engines if you reuse the front exhaust and make other minor mods, but we recommend against it. There are a few similarities, but lots of differences. These engines are the toughest of the 70s, but are also the rarest and hardest to find parts for... even simple items won't interchange, so we recommend only swapping in an EA71.

Swapping an EA61/63 to an EA71:

You will need a complete EA71 to do the swap, but this is a bolt-in job. If you get a motor with electronic ignition, you will have to reuse your old distributor or get a spark box. You must use an EA71 pressure plate and flywheel with your old clutch disc. Late EA63 shared the wide EA71 bellhousing, if yours did not then you will have to also use the EA71 bellhousing and starter, but this is still an evening job!

Swapping an EA61/EA63 to an EA81:

To swap in an EA81, you will have to change your transmission and gear shifter. The EA81 will not bolt up to the older transmission, and the older bellhousing won't bolt to the EA81. The engine and transmission mounts are identical so its still a bolt-in job, just more expensive.

Swapping anEA71 to an EA81 or vise-versa:

Honestly replacing an EA71 with an EA81 is silly, the last 1 bbl EA71 and 2 bbl EA81 that rolled off the assembly lines only have a 4HP and 11/lbft difference. This is easly obtainable by the addition of the appropriate 2bbl and distributor on a stock 1.6 motor.
If you still wish to pursue this, you only have to watch out for bellhousings. 84-87 EA71 and all EA81 are direct swaps, however 76-83 EA71 had a 1” narrower block, and the bellhousings are incompatible so you will also have to swap transmissions along with intake and exhaust manifolds. You can re-use your original distributor, (or the 83-87 2wd ND one). Heads will also swap in pairs.
Heads are up to you, if you have them shaved and ported/polished one is no better than the other. The only exception would be that in late 83, EA81s started coming with hydraulic lifters instead of the solid ones used for many years. You would have to have complete matching heads, cam, lifters, and pushrods to swap over to hydraulic but its a bolt on feat, even for the EA71. The EA71 cam is rougher than the EA81 cam, but there is an after market unit available that dwarfs both. Also, 76-81 EA71 have thicker piston rings and higher compression than all other EA-Engines.

Swapping in an EA82:

The EA82 can replace most EA engines with some work. The EA82 will NOT fit into a 70-74 vehicle, and will barely squeeze into a 75-76 vehicle with mods to the frame rails. However, an EA82 will fit in all 1980-89 with bolt-in ease, if your EA82 is carbureted. If yours is FI, you will have to cut and splice wires, cables, hoses, and more. It will be a tight fit, so you must use an electric fan and ditch the EA82 one. Distributors won't swap, however to simplify the process and have a non-computerized unit you can use an 85-87 EA82 carbureted distributor because the two-wire hookup is the same as most EA71/81. Once again, lookout for bellhousings, remember the EA82 and EA81 are the same, meaning you can't replace a 76-83 EA71 without using an EA81 transmission.

Also, watch out for minor EA82 differences:

SPFI/Carb Heads are nearly identical and offer a 9:1/9.5:1 on a non-turbo block.

MPFI/Turbo Heads are identical except for the extra oil and water ports on the turbo head. A non-turbo head can not be modified for OEM fittings, but the turbo head fittings can be blocked off for non-turbo usage. These offer an 8.7:1 compression on a non-turbo block or 7.7:1 on a turbo block, (difference is the pistons).
All non-turbo camshafts are identical year to year, and have a larger lift and duration than turbo cams, good for a calculated 5-10hp on a stock turbo motor. Finally, use of non-turbo pistons in a turbo motor WILL work perfectly, and is how we rebuild ALL of ours. This will give 130hp instead of the meager 111hp, the only drawback is you must either retard the timing 2 degrees or use premium fuel (93). Add non-turbo cams to that and you have close to 137hp!!!

Note: All information is from www.prosubaru.com. Their web site is no longer available! I stopped typing at this point do to the amount of information already available on EJ swaps on USMB.

#2 stealth


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Posted 15 February 2010 - 12:03 AM

learned something new :)

#3 MilesFox


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Posted 15 February 2010 - 12:31 AM

might i add that, when replacing an ea81 with an ea82, clearance to install the engine is gained by removing the distributor, install the motor, and reinstall the distributor to make clearance around the master cylinder. I have had to cut the mout tab off the right side of the disty and clock it all crazy for the vac advance to clear the MC

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