I recently met an interesting fellow. We have a Sunday morning car meet up in the large parking lot behind a coffee shop in lovely downtown Orinda, CA.

I’ve only been to three of them, but I’ve seen some pretty wild cars already. At the second one, I saw what looked like a Cobra of some kind but slightly different. The hood was open, I took a look, I’m thinking that’s way too small for a 427. I look closer and it’s a double overhead cam six, and I saw the word Bristol in the casting.

Then it hit me, I was looking at an AC before there was a Cobra. The owner is a pretty good dude, very savvy. I told him I had thought about putting a BMW six in one of those, why would you want a 427 boat anchor upfront in a small car like that. He liked that idea.

The next week he showed up in a Ferrari mid-engine bad ass looking machine. He is apparently well fixed.

I’m thinking about suggesting that we actually try to build the smaller Factory Five Cobra knock off with a high-performance 2 L. Search indicates the dry weight on those things is about 2300 pounds.

The Honda K20C1 Crate Engine sounds like a hot four-cylinder: 306hp, torque 296 lb-ft.

I’m going with 2 L because then we could have the option of selling it to some racing team if we got tired of it or wanted to build something else.

One fantasy engine idea would be to somehow get a hold of the early BMW M20 inline 6, as seen in the fabled E30, of which I had two. Seems like if it was properly tuned you would get more punch out of six cylinders than a four with the same displacement. Might be pretty hard to get one of those engines however.

The Honda motor is $7000. Seems like a reasonable price. But I know next to nothing about racing I hate to tell you. I’m not sure if there is a non-turbo clause or what.

So far, I’m having trouble discovering if you really save all that much weight with the 2 L engine. Here are some figures I found, not sure how accurate they are:

K20C1: 403 lbs

BMW N20 4cyl: 307 lbs

Ford Coyote 5.0: 443 lbs

Ford 427: 675 lbs

Chevy LS1 293: 500 lbs

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

Sounds like a good idea to me. You could probably pick up a Honda S2000 and get the same "feel".

I've got an old mid 00's BMW 525i behind shop you can have engine and transmission out of. It has the reliable 6 cylinder in it (I do not remember designation). It was brough to me years ago for a head gasket job. The guy could not afford the job and then he died. Been sitting there for a few years now.

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Jim

Most 2.0 turbo engines punch around those numbers. The 2.0 in my sky is easily north of 300hp and would do nicely in a cobra. 7k will get you a fully built engine with forged internals. A "normal" engine will run about a thousand and can take about 400-450hp.

In the ford family the 2.3 ecoboost engines (as seen in mustangs) would be a good option.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Why such huge engines? Forgot about this one? But you gotta feed it rice
>

https://newatlas.com/nissan-zeod-rc-engine/30611/

Nissan's engine development recently has been quite interesting. They are also putting variable displacement variable compression engines in infinitis now...I am not sure if the engine above is part of this family but neat engineering nonetheless. Jury is out for durability.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

They must know something, hasn't been about 10 years since this was proposed for racing? Did it go anywhere?

That Nissan motor would be about impossible to get I’m pretty sure not to mention incredibly expensive if it was available.

I was talking to my excellent mechanic buddy today, he’s the guy who put an LS into a Porsche 928. He got it cheap because the original motor was shot. I asked him what he thought about putting a BMW six cylinder into a kit car. He said it would be difficult, getting the wiring harness and the ECU hooked up correctly could be tricky. He is much more in favor of an LS or a Coyote.

I don’t really see the point in having a car that weighs 2300 pounds having 500+ horsepower, or even 400 from a V-8 especially when you can get 300 with a four-cylinder.

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

I appreciate the thought, it’s a long ways to haul an engine though. I suspect that’s an M52 or M54. I’ve not had experience with those, but they have a pretty good reputation.

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

The LS is compact and light (at leasy the aluminum block versions). Your mechanic will recommend an LS likely becaude they are plentiful and extremely widely documented. There are literally books and DIYs for "put an LS in anything" with standlone ECUs and adapters for pretty much every size and shape of things. It is by far the easiest option for a swap.

I don't see the point of a BMW 6 unless you are dead set on the silky 6cyl feel or ITBs.

Again, the GM ecotecs would be my go-to for a 4cyl rwd platform. They are easily modified, widely used in a number of models and have been around for a long time (they are derived from the old saab turbo engines from the 90s).

Another widely supported platform would be subie flat 4s. Not sure if itd fit in a cobra, but it would turn some heads. Some other factory five kits use subaru engines for their powerplant.

overall there is a reason the LS is such a popular swap engine...its cheap, compact, light, super extensive aftermarket, and has been put in practically everything.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

It took me a while to come around to the apparent fact that the Detroit OHV setup has its merits. Quite a bit more compact than DOHC, and I suspect lighter and more reliable as well.

I do like the sound of a BMW six however. How many headaches you’d be willing to go through for that is a good question. I miss the hell out of my E30s. I’ve driven a couple of E36s and one E46 and I didn’t like them as well. They weigh more, I think about 5, 6, 700 pounds more. I’ve heard from people in the know that the M20 is bulletproof compared to the M50s. SOHC and timing belt instead of a timing chain. Changing the belt is a semi PITA, but at least you don’t have to pull the engine like on a mid engine Ferrari. I know a belt is quieter than a chain, not sure if it’s any more reliable, as long as you are in the proper age/mileage range.

Another kit car that is a real magnet is a Beck Spyder with a Subi. Hoovies Garage did a show featuring theirs. When I was still in junior high in ‘67 Car and Driver magazine came out with a road test of a Meyers Manx with a 90 hp Porsche four-cylinder. It had big ass tires, they said that with those tires it would out-handle and out-brake any sports car they had ever tested, and this with the pre-super beetle torsion front suspension and drum brakes all around. Of course it only weighed 1200 pounds. Ever since I’ve had this kit car bug. I’ve never built one of any kind. I gather now they put Subis with 150+ horsepower in those guys and you have to be careful not to pull wheelies.

Hoovie’s Garage:

https://m.youtube.com/watch?v=8bJUDIYXkls

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

For a mild cobra consider a small block ford like they had originally. Simple and durable.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

if you are really into BMW sixes, the why not a big six, M30? Bulletproof, plentiful and you have a choice of a super simple reliable EFI with just 1 ECU or...can be carbureted like the earlier ones. The I6s are silky smooth and give you a wide power band. Metric Mechanic offers great support for them too.

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

My original thought, if I had Jay Leno garage money, was to get the E34 M5 motor, the S38B36, about 310 NA hp. But a more regular M30 would be no slouch and much easier to come by. I’ve driven two E34 535i models in my days, curb weight between 3360 and 3400 depending on the website, and those suckers got up and moved with 210 hp. Put that engine into a car that weighs 2300 pounds? OMG, I don’t think I would need to go any faster.

But the weight savings is not as significant as one might hope for. It can be difficult to find the specifications on the weights of various motors with all the accessories attached. So far what I’m coming up with is about 400 pounds for an M30 and about 530 for a 5.7 L LS1. I’m not even sure miles per gallon would be way better with the M30. Not a huge factor, perhaps.

I once saw a Cobra spun out on a raised island on a public street. I’ve seen video of other Cobras and Dodge Vipers doing likewise. I’m thinking why pay a lot extra for gas to enjoy the thing if that horse power is not much good for anything except getting you in trouble.

I think the fact of my 300D looking pretty nice these days helped me to get a foot into the scene down at the coffee shop. There have been some nice cars. A cherried out Morgan, a 1980 BMW mid engine something or other, Euro only I gather, it has the M88 I think. Also, a couple of Porsche speedsters, split window VW beetles, and a Bentley looking sweet.

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

I would think something like the 289 would be plenty. Factory five sets their kits up to accept a Ford coyote, I think those are about 5.0.

What motor does yours have?

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Te futueo et caballum tuum

1986 300SDL, 362K
1984 300D, 138K

Yeah that was most likely a BMW M1, rare and very pricey bird. Running good examples trade for north of half a million USD.

A ford 289 would be in keeping with the character of the original.

good luck, sounds like a fun project

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)