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C3 Corvette Stingray to Flex Fuel/Swapping engines? Or, Tell my if my boyhood fantasy can be a reality Answered

Short story: How hard would it be to drop a new, maybe flex-fuel, oh-say-maybe-an Impala engine into a C3 Corvette? Long story: I love Corvettes. A lot. I have decided to save up enough money over the next two years to purchase a C3 (1968-82) Corvette, and bring it up to modern motoring glory. I've been poking around, and looks like I can get a POS for about 10-15 grandios americanos. ANYWAY I'd like to replace the old engine with a nice new fuel injected, computer controlled, more efficient engine then whatever is inside. All I'm really after is the body. Frumpy 70's interior and matching engine numbers be screwed. My question to you: Several new Chevys are flex fuel, how hard would it be to get a wrecked car (I'm thinking an Impala might be about right), take out the engine and computer control goodness, and stick it in said 'Vette? My plans for the Corvette, I'm thinking a '80-'82 if I have choice, I'd totally get a '64 split window, but they be EXPENSIVE: ~Complete interior overhaul; brushed aluminum dash (retro-motorfied-Apple-esque?), sound system etc... ~New paint job; blue with silver racing stripes (like the new Shelby Cobra, reversed) ~New engine, and what ever mechanical tune-ups are required. ~I might make the sunroof removable ~Whatever else comes to mind in my owner ship of the most awesome thing on 4 wheels Thanks!!



I would just like to update; I bought a 1990 with a new ZZ4 V8. I am in love with my car.


52k miles, automatic. Currently working on getting it ready for autocross. At 55mph I get 32ish mpg, haven't felt a need yet to get all alternative fuel with it, but I have seen a cool petrol to electric swap on a C4.

bumping a dead thread!! No one here has mentioned the Megasquirt ECU? The newest version can actually use a GM flex fuel sensor and is exactly what you needed..you can put pretty much any engine you want in and tailor all the settings to your desires. And in the spirit of instructables you build the ECU yourself!


5 years ago

So... i think maybe you're over complicating things quite a bit. I looked into this issue back when i was looking to convert my car over to natural gas a few years ago....

Flexfuel engines are designed to 'adapt' to various fuel sources, however, the necessity of that adaptability arose out of the specificity of fuel injection systems. If you get rid of the fuel mixing system, you have your engine with the fuel adaptability you're looking for.

Carberators are actually more flexible in their ability to mix fuel then fuel injectors. Fuel injectors can lead to slightly better engine performance, but every type of fuel that goes into a fuel injector requires adjustment in order to be able to burn right in the engine. Flex-fuel engines allow for dynamic adjustment in the engine as the fuel is consumed (the computer control unit adjusts the valve timing according to the oxygen sensor readings); Carberators do this by adjusting the fuel mix, prior to being combusted in the engine.

if you want a flexible fuel sports car, you might consider seeing if you can have your vette retrofitted with a carberator.

just a stalker resurrecting your thread if any of you are still active..... did you wind up getting a c3 and doing a swap? I have been looking for a swap myself... however I am currently thinking a crate engine and the accompanying rebuilt 6spd.... or the cheap option of getting an LH8 and trans from a wrecked vehicle

I dont think that a new motor is really what that type of car needs. A classic American car should have exactly what was put in it, keep it the way that the engineers designed it first. Adding new things to beef it up may look cool to the inexperienced car lover, however, to someone who knows what hes looking at, he wont be that impressed. Keep it original and it'll be cooler, worth more, and more attractive to the expert car lover.

you don't want a corvette for your fist car because they are fiberglass and if you wreck them they are totaled but yes it is possible to do my friend has done it but 2 years later it got totaled by an 18 wheeler BTW the pic that is on the far right the one with the silver car with blue racing stripes that is a mustang shelby edition cobra

Fiberglass is also easy to repair. Besides, it wouldn't be my first either. I have a first car, a '93 buick century. If I was black it would be a tight car to have but as I'm not... I know the one on the right is a cobra, I put it there :P It's the paint job I want, just reversed.

i could paint it easy once you get it done plus if you need help i am there

You're gonna have problems with the tranny/chassis mostly. I'm willing to bet you don't have the tools to do much of the work yourself (interior is relatively easy; mechanics is the issue here), so the bulk of your spending will probably be paying someone else to do this for you. If you really have an interest in mechanics, I suggest getting a job at a local garage as soon as you can. Other than that, sounds do-able, although difficult and expensive... Make sure your budget is realistic and keep saving up!

I think you can do better than the $10k-$15k pricetag. You should be able to get a decent body with engine/tranny problems for half that amount. As Nacho mentioned, the engine-to-tranny bolt-up will be the issue. Also, there will be serious computer issues between old/new engines and transmissions. I wanted to put an old trans in my wifes LT1 Z28. My trans guru friend said it wasn't worth the hassle of dealing with all the sensor/computer issues. On a serious note, if you can stand the '84 model, they are cheap! Nobody likes to work on the crossfire engines. Also, if you were interested in an '85, I'd make you a good deal. (I have bills to pay!) The fuel pump (in the tank, not the injectors) went out, and I haven't had time to mess with it. It's been sitting in my parents garage for about a year. And finally, if I had the dough, I'd go with a '72 or earlier, as I like the chrome. But that's just me.

Your estimates bring a warm glow to my heart - more cash for goodies! I'll have to figure something about what to do about the computer though. The big reason I'm after a C3 is I'm just nuts for the stingray body, 85 is unfortunately just not stingray. HOWEVER if mom lets me autocross, I would love to get C4 or later to race (I aint riskin screwin up deh chick chasin car!!). What's the engine in yours? So I'll just have to see what happens over this next year or so. The earlier C3's, have a sharper body look too (which looks cool, just not as "edgy" as 78->) as well as chrome bumpers, I think it's way cool but boy they cost a lot more than 78-82. And I'm thrifty....... Let's just put it this way, I'm going to own several of these thing it looks like.

My '85 has a 350. It's TPI, -Way more reliable than the old crossfire, but not nearly as awesome as the big-blocks of the late '60's - early '70's. And I agree about body styles. For me, anything from '58-'72 is AWESOME. I like all the others, but those are the ones that tempt me towards idolatry.

grrrrrrrrrrr..... Now to go get job and make me moneiz to buy carz... Heck, any corvette 'cept C5 iz my idol. The new ones they are producing look awesome, and word is that they are going back to the stingray style (WOOT)

> if you can stand the '84 model, they are cheap! Nobody likes to work on the crossfire engines.
. The consensus of ppl I've talked to through the years (I've never had nor worked on one) is that the crossfire is a huge POS.
. Chrome is good. :)

That's what I'd always thought. Then I met a kid at work with an '80s model Camaro, (and a Crossfire). He said there's a fellow in Ga. or Al. that really knows how to sort them out. I don't know what he did to that one, but it was fast AND unbelievably reliable. I still don't want one. Other than that one kid I've NEVER heard a good word about 'em.

. The only real big problem I see is whether or not the flex-fuel block will bolt up to the tranny. None of the wrench-heads I called knew. . If it will bolt up, then you have it made. You might have to buy/fab some motor mounts. If the ECU is expecting a "smart" tranny, you may have to work around that. . Tuning the exhaust for the ECU might be difficult. . One guy (an old Vette nut like you) suggested getting the whole drivetrain (at least engine and trans) from the FF donor. . If you do have a number-matching engine, save it. I'm guessing most Vette drivers won't want a FF engine. :) . . How did that Cobra (last pic) get in there?

Excellent! I'll have to see what I end up with, but replacing the drivetrain did come to mind. In the bit where I was blabbing about my plans, I said I was after the color scheme exactly opposite of the pictured cobra, but I REALLLY like those colors.

> I said I was after the color scheme ... . Oops. Didn't read that part. Skipped over it because it wasn't important to the mechanical part. . . I have several friends/acquaintances that are good Old Chevy mechanics and have tons of trivia stuck between their ears. I'll be happy to pass on any questions.

Thanks! I did a little bit of poking around and I think an Impala engine might do me well. Or would that be too small and bastardize my Vette?

. Well, many would say that anything other than the motor that came in it is bastardizing. ;) . Anything less than eight cylinders in a Vette would be sacrilege. Any of the modern LS-series motors should make you happy, but I can't tell if any of them come with the flex setup and I don't think they will bolt-up to an old tranny (not sure). . Any idea how the HP per CID compares between old gaso and new flex? Since modern engines have a much higher HP:CID ratio, you may be able to get by with a six cylinder and still have plenty of power ... but it's not going to sound as good as an eight.

I looked into what's in the Impala, and the best ones have are a 5.3L V8 and a 3.9L V6. If I can afford it, I'll try to get the V8

Mmm, you'll have to look at the engine mountings and connection to the transmission. Those are probably your biggest problems. Go with new engine and gearbox it might be easier. I'd wait until you can afford the Corvette, but keep an eye out for engines while you're doing so. L

Aye thanks. I'm planning on saving up for it, in the meantime I'm looking at goodies and scrap cars and other bits and parts I may need.

Get a supercharger that sticks out of the hood (even if you don't hook it up)! L

Yah, I'm thinking of getting an aftermarket hood. All of these things I will fool around with in two years :D

Tis a very nice car ! I like your plans to restore it too, how will you get the money to buy it ?

No, it just doesn't pay as well as numerous alternatives.