Hi All,
My name is Aaron. I've been lurking on this site for years, learning from all of you who are kind enough to share your projects and the challenges that go along with them. In an attempt to keep me motivated on my project and as a way to create a place for me to ask questions as they come up (which they will, frequently), I decided it was time to start a proper build thread. I’m not a novice when it comes to tools, fabricating and most things automotive, but I’ve never attempted an engine swap before, and most things electrical tend to stress me out. That being said, I love a good challenge and I’m not afraid to fail.

I purchased this car in February of 2020, just before Covid lockdown. I got off to a pretty good start repairing the rust and trying to make a solid chassis for what I thought was going to be a stock-ish restoration (some of that work documented here: http://www.914world.com/bbs2/index.php?sho...ty+jack+points). Then, after watching all the great engine-swap builds on this site, I changed my mind. I knew I wanted more horsepower, but I couldn’t justify the cost of an air-cooled Porsche 6-cyl and I didn’t want to lose the trunk to a big V8. For a while, I was considering keeping the original engine from the car and using a tunable fuel injection package, but for the total cost, the bang for the buck just didn’t seem there. So, I settled on the Suby engine. After some research and some purchasing mistakes, I ended up buying a 2002 legacy outback donor vehicle with an EG25 engine. I harvested the engine, the ECU and whatever else seemed valuable. After selling off the old Porsche engine, transmission, all of the FI components and the saleable parts from the donor Subaru, I probably ended up in the black, financially.

Since buying the car in 2020, I’ve gotten pulled away by many other, more important projects, so I’ve only been able to do little stints of work on the car. I’m optimistic this time, that I will be able to finally dedicate some quality time this winter and hopefully make some real headway. I haven’t been great at documenting the little things I’ve done on the car in the last 2 years, so I’ll start this thread off with some of the things I did actually get pictures of and a summary of where I’m at now.

The day we met: Click to view attachment
The first attempt at a Suby Engine (EJ22): Click to view attachment
The second attempt (complete donor vehicle):Click to view attachment
My crazy, home-built cable shift linkage:Click to view attachment
My home-built engine cradle: Click to view attachment
Shifter from a boxter (slightly modified): Click to view attachment
Some suspension ear reinforcement: Click to view attachment

Great; we all love build threads with lots of photos so we can enjoy the ride with you. Good luck this winter.

Nice work so far. That shift linkage looks really nice.

Looks great. Will you be able to drop straight down a few inches from the manifold with the exhaust and clear your engine cradle? Now is a good time to weld a few pieces of bushing stock to the cradle so that it will accept some caster wheels. Makes for a quick install or removal.

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Good timing Kent. Exhaust is what I was working on this weekend and that was going to be my next post. Here are some pictures of the header I made for the right side. Aside for a few welds that I rushed, I’m pretty happy with how it turned out. I was considering using exhaust clamps of some sort to join the muffler to the header pipe, but I think I’m just going to weld it right on. I’m sure the muffler will outlast my header pipe anyway and the whole exhaust is so short it will be easy to remove in one piece. I plan to weld a hanger on the muffler and attach it to another hanger on the underside of the trunk with a rubber exhaust mount.

Any suggestions as to where I might mount the O2 sensor bung?

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Nice looking fab work you have there. Weld the bung within 12" of the flange and somewhere between 9 & 3 o'clock. Moisture is their enemy so stay above the bottom half and keep it accessible for future testing and/or replacement. Looking back I wished that I would have fabricated the cradle to accept hangers for the entire exhaust system. That would have been better than having mounting points on the tub. You're not exaggerating about the short exhaust. I ordered 10ft of 2" tube and it is still sitting in the corner. Nothing but fittings and flanges on mine.

Do these Subaru engines not benefit from the ol' equal length exhaust runner thing? I'm not picking on the design, it's just that I've seen a few after-market Subbie headers and none of them are anything like what you hear about being designed for optimal performance.
Is it down to available space (totally understandable) or am I missing something?
Your work looks lovely, by the way, so again, not a dig at you.
I'm going to be fabbing a complete exhaust for a buddy's Subaru swap and was planning something equal length - so I'm genuinely curious.

@76-914 , thanks for the O2 sensor placement advice.

@tygaboy , pick away, by all means! That’s really the whole reason for the thread in the first place!

Below is a picture of the engine end of the stock manifold. (Looking at it more objectively now, I realize that the “runners” are sort of equal lengths)… However, this doesn’t fit with the engine cradle I have. In my mind, I was making something similar that cleared the cradle. If anyone thinks my design is going to cause issues, I’d rather know now! Don’t hold back!

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Tygaboy is right!

Every cylinder has an "optimal" primary diameter and length for maximum VE at a specific RPM range in the engine.

A primary length for 3-4k RPM will be different than the exact same engine at 5-6K.

If you're racing and always above 5k you need one length, and a streetcar will have better overall performance with something quite different.

How much of an improvement is the real question here. The OEMs break these rules all the time with weirdly different length primaries that seem work OK in real life.

Yours are already built; I'd try them like they sit.

It almost looks like you went slightly larger on the exit tube past where the primaries blended?

I think that will actually function OK.
I think you will be fighting cracks just past the blend from now on...
That area will be getting double the heat versus separate longer primaries.
I'd still want to try it if I was in your shoes.
Sounds like making a dedicated tuned length separate primary header might be a bitch with that engine.

I'd look at a NA Subaru high performance header (if such a beast exists) for primary dimensions.

@technicalninja Thanks for the info! I love the knowledge that everyone brings to this site! I knew about the equal length primary thing, but I really didn’t think it would make much of an impact for my relatively anemic 2.5L NA engine. I like the idea of “just trying it”, but I’m already thinking about how I could redesign. The other thing I should mention, that isn’t obvious from my pictures, is that I am planning to have two separate exhaust runs each with their own separate muffler. I’m going in this route primarily due to available space and to simplify the exhaust pipe construction. So, cylinder 1 and 3 exhaust runs never merge with 2 and 4. Am I asking for trouble with this? Can anyone educate me on the reasons for/agsinst merging exhaust runs on a 4-cyl NA engine? And what about the sound? Am I building something that is going to sound whacked? For reference, the mufflers I picked are flow master delta 50 series. This choice was based primarily on size and cost and had nothing to do with performance.

You could put 3 into 1 and it will still outperform that old air sucker. Just build it. I'll bet you will thrilled with your outcome. I've been waiting for someone to build a NA 2.5. 165 hp won't be anything to sneeze at.

You could put 3 into 1 and it will still outperform that old air sucker. Just build it. I'll bet you will thrilled with your outcome. I've been waiting for someone to build a NA 2.5. 165 hp won't be anything to sneeze at.

6 cylinder or less should be run through a single pipe.
8 or more should be two that come together after the collectors in either a H pipe or better yet an X.

Look at Tygaboy's LS3 car for example. His stuff is bad assed!

The above is my opinion and it has more to do with the exhaust sound than scavenging.

4s or 6s sound like ass with 2 complete exhaust systems that never meet.

And here's a little dig at @tygaboy

You understand this stuff pretty well Sir...

Why haven't you applied 180-degree headers to the LS car?
I haven't read the entire 230 pages yet, maybe I missed that conversation.

Could have made it sound like a flat plane Ferrari!

I see what you did!

Going for that Ferrari shriek the hard way...

As I contemplate design changes to my exhaust, I decided to knock out something a little more straightforward tonight. I mocked up a hybrid CV axle.

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And the same axle on the passenger side. I’ve got about 1/4 to 3/8” of free play when the distance between attachment points is at the shortest.

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Got them boxed up with two spare 914-4 CV shafts to use for the new axles and will be sending them off to Dutchman Motorsports tomorrow.

I’ve had more distractions lately than I expected, but I have some updates to share…


First, the hybrid axles from Dutchman showed up. They are really nice!

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And, I finished the exhaust! This was definitely harder than I expected! No right angles anywhere and very challenging to find ways to hold pieces in place while I measure/adjust/tack in place. My car has a factory rear sway bar and my engine cradle is kind of clunky back by the rear of the car. Those two things, plus the relatively large muffler that I chose, made it very tricky to find the ideal position for the muffler.

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Couple more pics of the complete exhaust system.

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After finishing the exhaust, I felt like I needed a different type of project. I got out the crusty old rear valence to see if it could be saved and converted (properly) for a right-hand tail pipe exit.

This is what I’m starting with. The big dent on the side opposite the factory tail pipe cutout was the previous owner’s solution to a right-hand tail pipe. (This car had a very clugey turbo and the cobbled-together exhaust exited on the right.)

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After scraping a pound of mud and tar off the backside and spending a few hours with a hammer and dolly, I got it reasonably straight. I’ll give it a good cleaning, strip the remaining paint and start measuring where to cut for the tailpipe now that I have the exhaust finished.

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Your fabrication work kooks good. Exhaust routing requires a bit of thinking and fiddling. There isn't a lot of room for an exhaust system on these cars. I still have an untouched 10' section of exhaust tubing after doing 2 of these conversions. It's all fittings and mufflers. There wasn't enough room for any piping on mine. I'm impressed that you were able to incorporate a crossover pipe.

Looks good! I just wrapped up my Suby exhaust so I can relate. I bought headers and only had to fab from the header flange back. I like how close you kelp the pipes to maintain ground clearance.

Buddy of mine in New Mexico is building "Physco Beetle" and fabricated this exhaust header for the boosted Suby engine; turbo V-band clamp not attached in pic. Smooth transitions, proper od / gauge tubing, and all joints smooth and de-burred, prior to (TiG or MiG) welding are your friends. Unlike n/a engines, "Boosties" are all prone to (unwanted) back pressure as the exhaust pulses tend to slow down at the hot-side turbine inlet >> unlike a free flowing & scavenging collector in an n/a scene. Turbo sizing is already done for you, as you will be using the factory designed OE turbo that came with the engine.
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It’s been a while since my last post, but I’ve been chipping away at stuff. Here are some updates.

Shifter is mounted
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Cleaned up the driver’s footwell and welded all the access holes in the floor pan.
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Finished the metal work on the rear valence (for now). I’m undecided if I’m going to keep this valence as is or make something else. I’m going to wait to see how I feel about it once the car is on wheels.
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Did a rough install of the hybrid axles with the new exhaust and all the rear suspension parts to check for installation issues and adequate clearances. I also wanted all these parts in place for when I’m figuring out the shift cable routing. This was a good motivator for me.
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Next up is brackets for shift cables, and then start working out the pedal box mods for the hydraulic clutch.

It's good that you're back on it. Should be a nice reliable 914 when you're finished.

Well, a year went by since my last post… good thing I don’t have a deadline for this build! Over the last couple of months, I have been able to spend some more time on the car. Here are some progress pictures.

To get back into things and to test out my new welder, I thought I’d try making a shortened oil pan. I know these can be bought, but I wanted the exercise and I knew a homemade version would be cheaper. Started by cutting up a spare to see how things looked.Click to view attachment

First I thought I’d try to keep the original bottom section with the drain plug, but it seemed like it was going to be too hard to join the parts back together and get it to look good like this.
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So I decided I would make a new, flatter bottom and I cut up the brand new pan I bought from Amazon. I made my own transition section to retain some of the volume. I also shortened the pick-up tube.
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Then, after a lot of forming, welding, grinding, checking for leaks, re-welding and more grinding, I ended up with this. I bought a low profile drain plug because the stock plug stuck down farther than I wanted. I measured the volume of the finished product and it’s about 1/2 quart less than the stock pan. That doesn’t seem like a huge problem to me, but I’m willing to listen to opinions from others.
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Next up, I thought I’d start figuring out radiator mounting. Originally, I was going to use a Mishimoto radiator and fans for a Celica like others have done, but I really wanted to be able to keep a spare tire in the frunk and I don’t like the idea of the collapsible spares. So, I bought a smaller, Scirocco-style radiator from Amazon. There are lots of variants to choose from and I ended up going with one that had mounting points for fans on both sides of the radiator. Before I started cutting big holes in the frunk, I made some cardboard mockups of the spare tire and the radiator to see what this might look like.
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Satisfied that there was a way to make this all work, I went all in and cut some holes.
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My plan is to run both cooling hoses up the drivers side longitudinal. This portion of the chassis is still wide open from the rust repair I have yet to button up. With this plan, I wanted to keep the radiator inlet/outlet on the drivers side. But with the radiator configurations I could find, it was going to be tricky to route the hoses this way without a lot of clunky hose bends and fittings. So, I cut the hose fittings off of the radiator and had a welder buddy of mine weld some AN16 bungs in place. This gives me lots of options for AN elbow fittings, etc.
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While working in the frunk, I realized that there was some mediocre repair to fix some front end collision damage sometime in the past. The chassis supports near the headlight buckets were not straightened very well and were poorly re-attached to the front cross piece. Also there was a lot of Zeibart coating under the headlight buckets that was bugging me, so I decided to pull out the chassis supports, straighten them and clean under the headlight buckets.
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I ordered some Spal fans, some AN hose fittings and I made some parts to mount the radiator and mount the fans.
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That pretty much sums up where I’m at now. Hoping to finish the hose routing next and start on the heater core build.

Happy 914-ing everyone!

Very nice progress. I especially like the new tailpipe opening you made in the valance; nice touch.

I believe the Subarus run pretty cool (compared to my SBC), but consider ducting the radiator to force the air out the bottom. It’ll be more efficient, and help with what looks to be a shallow angle of the radiator.

Hmm regarding the shifter. Just wondering out loud, if the primary reason for the OE center tunnel is to mount the shifter & contain the rod/linkage, once removed is there a reason not to relocate the cable shift box/monstrosity lowered into that space?

Definitely an interesting idea, and one that I may spend time pondering further. I do still need space below the shift mechanism for throttle cable, fuel lines and hydraulic clutch tube. I really don't love the giant boxter shift base either, but I did shorten the shift lever quite a bit and there is some plastic I can remove to reduce the overall bulk of it. Many others have used the shifter from an MR2 which is much less bulky, but I got this boxter shifter cheap and just went with it.

I hid mine under a custom center console. Mine is the MR2 shifter but similar height with the mounting bracket.

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You should be able to cool the 2.5 with a much smaller opening unless you run AC in the south and drive in StopnGo traffic. Nice work

Yep. I’m hoping to do something like that. Love your whole build, btw!

April '25 update:

I've been able to spend several hours a week on the project. Progress feels slow, but I'm moving forward, (I think?).

I'm still working in the frunk trying to figure out all of the details for radiator mounting, hose routing, ducting, wire routing, spare tire mounting, etc. I feel like I've been spending a lot more time staring at the car and trying to make decisions on all of this stuff as opposed to actually doing the work. This part of the project definitely has me questioning my choice to convert to a water-cooled engine. Anyway... here's where I'm at:

After removing both structural panels between the front cross panel and the wheel wells, I welded some new metal to them and straightened them out as best as I could to better repair the previous collision damage repair. Shot these with some self-etch primer and welded them back in place.
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I then made a cross-member to support the bottom of the radiator. I went round and round on the design of this part and the best way to attach this to the chassis. I don't want the final product to look like a cloogey conversion so I'm trying to make the modifications look like they belong in the car to the best of my ability. Not sure I totally hit the mark on this, but I'm satisfied enough.
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It's a little tricky to tell what you're looking at here, but this is the underside of the radiator support cross member. Since this piece gets in the way of the wires that route from the fuse panel to the headlights/turn-signals/horns, I decided to keep the bottom open so that I can route the wires through this over to the passenger side headlight/turn-signal/horn. I will make some sort of flat cover that attaches to the underside of this so that I can access this area from below the car but still keep the road grime and water out of here. The mounting tabs in the center and welded nuts on either end are for the attachment of this future cover. The sheet-metal tabs are retainers for the wire bundle that will run from drivers side to passenger side (trying to duplicate the factory sheet-metal wire retainers).
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Finally, the cross-member is welded in (not the prettiest welding, my gaps were too big) and I filled in the hole in the front of the frunk floor. I was feeling pretty good about my progress at this point so I invited my wife out the garage so that she could marvel at my work. Her only comment... "when are you going to get to the pretty stuff?"
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Lastly, the progress on the hose routing... I'm pretty sure I'm going to get some negative feedback on this, but I've chosen to route BOTH coolant hoses through the driver's side longitudinal. Various factors contributed to this decision. I don't like the idea of going under the car (too much chance for damage, IMO) and based on the radiator configuration/location I have, I think this path makes the most sense. Plus, the driver's side longitudinal is currently wide open because of my rust repairs, so this makes it easy to remove the heater ducting and install two individual conduits in there to protect/insulate the hoses and make it easier to fish the hoses through during final assembly or if I ever need to replace them in the future. I plan to make a removable cover that will conceal/protect the exposed hoses in the driver's foot well. I know that having two big, hot hoses right near the driver's seat might make the ride a little warm. I'm really hoping it won't be unbearable!
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Here is a picture looking down into the area below the gas tank. The two coolant hoses will run in the little cavity that sits right under the torsion bar. The cavity wasn't quite big enough, so I cut it open and flared out the one side so that the hoses could exit next to each other in the frunk. The oval-shaped hole has since been filled in with a domed piece of metal that gives the hoses just a little more room at the bend. I made sure none of this stuff will interfere with the gas tank or the torsion bar.
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And the holes in the frunk where the hoses will exit. I'll use rubber grommets at all the holes where the hoses pass through.
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That's it for now. Thanks for looking!

Looking good!

Very very nice work....