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V8 Conversions



  • andre1969andre1969 Posts: 23,040
    I had to replace the fuel tank on my '68 Dart. Getting the old one out wasn't too big of a deal, but trying to force the new one back in was a pain. Once I was finished, I started up, pulled out of the driveway, and the car just died on the street. Luckily it was on an uphill grade so I could let it roll back into the yard.

    It turns out that there was a rubber connector in the fuel line somewhere back towards the gas tank, and all the pulling and pushing and yanking, with getting the old tank off and the new one on, ended up ripping that rubber part.

    Now, I don't know if a 1960 Mopar's fuel line would be similar, but it could be possible that there's a similar rubber part back there that's got a hole in it, and not allowing enough fuel to get through. Now if you had a leak like that, you'd think you'd see or smell spilled fuel. But I didn't with my Dart. I think the torn part was at a spot high enough that the fuel in the tank wouldn't drain out, but then it still seems to me that the fuel already in the line, between the rupture and the engine, would drain out. :confuse: But, maybe not. I did have the car jacked up in the rear to get to the tank, so maybe that was enough of an angle to keep it in?

    Anyway, my guess would be that there's sediment at the bottom of the fuel tank that's blocking the flow. Probably wouldn't be too surprising for a car that's almost 50 years old.
  • texasestexases Posts: 7,762
    It could well be a tank problem. Here are two more things to check before going to all that work. First, try to look at every inch of the line you can see from tank to carb, to look for kinked or pinched steel lines or deteriorated (possibly collapsed) rubber. Also, if you can get to it, you could try disconnecting the line at the tank and pump, and blowing air through it. It could either show the line is clear (meaning the obstruction is elsewhere), or it might even blow out something.
  • I have a 1973 Merc 450 SL Convertable in great shape. However, in typical elegant German engineering fashion, the V8 is a nightmare. Between the distributor, electronics, and some very odd pneumatics, the whole thing is impossible to keep in top running form. Fortunately I also have a Ford 5.0 L Fuel Injected V8 at my disposal that I would like to drop into it. The engine compartment has more than enough room to accomodate it. With the Ford power and the gearing on the Merc rear end, the combo should really rocket. But I would rather not engineer the whole transplant from scratch. Does anyone know of anyone who has an aftermarket solution for mating a Ford powerplant/auto tranny to this the Merc running gear?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    I have seen a 280SL done with a Ford 289 (and the trunk script changed to 289SL as well!) but they used the Ford transmission, which I would recommend. I can't imagine any kind of commercial adapter in existence---this isn't a very common transplant.

    Also I have bad news---I think the car will be slower with the Mustang engine, unless you are putting out significantly over 250HP. Of course, if your current engine is tired and ornery, you might notice a difference, but the stock car when new should have done 0-60 in about 8.5 seconds....given the porkiness of the 450SL I don't see how the 5.0 Mustang in stock form is going to better that by very much.

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  • Thanks. Yes the plan was to also use a Ford transmission. The available one I have is three speed auto with an overdrive 4th. The Engine/Tranny are actually out of a Ford Explorer XLT. If I can get the mechanicals sorted out, I will probably wind up converting the engine to a tricked out normally aspirated variant to get around the also archaic computer module in the Merc. I will do a search on teh 289SL, maybe someone has a webpage on it. I really like the badge change. Personally I would look into getting a couple of badges in the shape of spades (as in "Ace of Spades") made up for it as well.
  • thullthull Posts: 1
    I'm thinking also about doing an engine swap, have you started putting your ford engine in yet, and if so could you tell me how it is fitting or if any mods that need to be done to make it fit.


  • I noticed your conversations on the Mercedes motor swaps. I am in the process of doing one now, I am installing the 1976 Chevy 305 or 5.0L small block w/4 barrel carb and a chevy 4 speed tranny in my 1973 350sl (same as 450sl) This should push between 250 and 300 horse. If you install a motor that is close to the production year of the car you need not worry about emissions. I'm not sure about California laws on this. But this will free up a lot of space.
    Fortunately I have tons of valuable resources and I am a custom heavy duty Truck mechanic and My brother has been in the parts business for 20 years.
    I am fabricating motor and transmission mounts for this swap.. At my job we have a person that specializes in drive trains, he will be cutting my mercedes driveshaft and will weld it to a chevy yoke for the transmission, then he will balance it. This will allow the use of my mercedes rear end.
    I have done the measurements and research and this seems like one of the easiest ways to install a more affordable and more powerful motor. Let me know if I can help anyone!!!
  • 800sl800sl Posts: 2
    My turn to jump in.
    I am building a replacement front crossmember for the w107 body. This solves all the clearance problems with the steering box. And it doesn't matter if it's a Ford or Chevolet you will have clearance problems.
    I will also be offering a rear suspension kit. It will be a three link with watts linkage to support a 8.8 or 9 inch Ford.
    Why the major up-grades you ask? Well I'm installing an injected 468 inch big block Chevy backed by a T-56 six speed and a 9inch Ford. Oh did I mention it's turbocharged?
    This otta make this pig junp!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    Well both you guys keep us posted on these interesting projects, please!

    If you want, you can start your own pages, and post photos there. It's also a great way for you to store your own restoration record in one place. Let us know when you do that, if you do.

    As for California, if you install a '76 motor, in theory you'd have to pass '76 emissions testing. As a '73 car, there is no smog testing required, so you may never have to deal with this issue unless CHP stops you and wants to bust you for an engine swap. Not likely.

    I think a 350SL differential could handle a normal 305's torque but not that stroker motor! The Mercedes overall structure is very solid so I'm pretty sure you won't get any chassis twisting----but you know, that depends on how much power we are talking about. I've certainly seen big block motors twist and crack stock frames.

    Are either of you expecting difficulty in getting the stock shifter console to sit properly on the floor pan, or will you have to build something there? Will the AC still work (not that it ever did on a 350SL :cry: )

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  • 800sl800sl Posts: 2
    I'm going to build frame connectors and at least a four point roll bar ( got to be safe )
    The turocharged big block will reach 700HP on pump gas, and yes the A/C will be retained and steering will be upgraded to power rack and pinion. I'm going to go with the stock climate control for now because everything works but if anything fails it will all be replaced with a Vintage Air system.
    And remember. The front suspension conversion will be a bolt in. The rear suspension may take a bit more than a "bolt in", we'll see.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    If I may offer a tip---if you can afford it, go with vintage air right away. The Mercedes system is not very good and repairs are quite expensive.

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  • I'm interested in your rear end kit. Please post or give me more information.

    Secondly if anybody is familiar with 450SL rear ends please tell me if there is another Mercedes that has direct replacement third member with lower gears than the stock 3.07. I searched books, aftermarket manufacturers and wrecking yards but so far everything I've found looks like a major change. The 240D looks to small to mess with and the larger car have higher gears then the 450.
    please advise,
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    The 300D and 300TD is geared 3.46

    The model 250 1975-1985 was a 3.92 but that's a 6 cylinder car, so I dunno...

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  • 660ce660ce Posts: 1
    I've been harboring fantasies about a swap for so long. I built a Healey Sebring MX kit (don't like Chevys in Cobras) and have grown tired of feeling like I'm in a carnival ride AND still can't smog my "66 El Camino" 396 motor in California due to an aggresive street cam, 10.5 compression, port-alignment, etc.

    I know I'm jumping in amongst a number of SL swappers, but I'll be "dropping" my bowtie 402 big block into a freshly purchased '84 300CD. Not a beauty, but she's solid and no rust. Body and paint will come after she's road worthy... maybe ;)

    Very interested in cross members and options for Ford 9" installations even though I'll be trying the stock rear for the initial go. It's just too cheap to cut-and-balance drive lines when you have all the parts for both Chevy and MBZ.

    I get the illusion that there are a number of converted MBZs out there, but they're harder to find than expected. I was beginning to think the only connection was the guy that swapped his Rustoleum-Flat-Black 190e in to a V8 to do bigger drifter-burns..... Thanks for hosting this thread. There IS comfort in numbers, if not safety!

    Cheers for now,
  • fintailfintail Posts: 41,900
    Several years ago I knew of a W123 that someone had dropped a Ford 302 into - apparently it worked well. I don't know any of the technical details however.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    I once saw a Ford 289 dropped into a 280SL Pagoda and it was beautifully done. No doubt it devalued the car considerably but I'm sure it was way more fun to drive. The stock 280SL was always, in my opinion (and as a former owner) a very feminine car.

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  • fintailfintail Posts: 41,900
    I won't disagree about the femininity. The car has somewhat delicate lines, especially with the thin-pillared hardtop on. It doesn't make any pretense of being an extreme car.

    At the Vancouver Auto Show this year a customizer had a 190SL with some form of Corvette engine. It was also beautifully done, but certainly a way to burn a lot of money.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    Given that a correct and restored 190SL can be worth $80,000 and that a 190SL with a Corvette engine worth perhaps $25,000, that wasn't so smart----unless of course the 190SL was trashed to begin with and ready for cutting and customizing. Nobody really wants a 190SL with rusted floors all patched up, or severe body damage that's been straightened out. So customizing a 190SL might not be a bad idea on that level.

    But really underneath the chassis, brakes, steering, etc. of a 190SL has very humble entry-level sedan underpinnings, so the V8 engine is only the FIRST thing you'd have to do to avoid driving a death trap.

    At least with a 280SL you get a car that is competent in handling and braking from the get-go.

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  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    It's well done. The engine bay looks radically altered, interior less so. Wheels ruin it IMO. Wonder what they did underneath?

    I saw a 190SL with a Chevy V-6 installed and it didn't require any alteration per se. It moved out smartly, too and looks perfectly stock.

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  • fintailfintail Posts: 41,900
    I suspect there's a lot of reinforcement underneath. I hate the wheels know what they say about a fool and his money. I suspect the person who had that car built has never been called sensible...but it least it isn't in wild colors.

    I'd like to see such a conversion with another MB engine. If one wants power, 5.4L V8, AMG-tuned, is known to be relatively bulletproof and is capable of a lot of mods. The old M103 and M104 I6 engines are very solid too.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    the problem with putting an American V8 in a small sports car is that you always end up with a "brute". You lose all the smoothness and sophistication and your SL sounds like a Chevelle if you don't take the time to build 'em quiet and balance them out. But headers and Flowmasters and you've got the wrong sound and feel for the car IMO.

    Also I find American engines rather unattractive unless they have cladding on them. They look like crude foundry iron with chrome stuck on them.

    Modern American V8s are more attractive as they are "dressed".

    My two cents is that if you are doing a V8 conversion into a pretty little foreign car, you've got to take care to do it right, and remember what you are building here. No headers, sensible mufflers, sensible intake system (a cut out air scoop on an SL---now REALLY) and tasteful wheels that match the car's lines and time period.

    And balance that engine, flywheel, driveshaft, etc.

    Even the Cobra 289s are much better cars as modern kits than they were when first built.

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  • fintailfintail Posts: 41,900
    I like the idea of putting a more modern I6 (or maybe a tuned V8 to be wild) in an old car, resto-mod vs resto-rod. The smallblock Chevy thing is a cliche and doesn't really belong in a German car.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    I'm starting to like the "Pro Touring" concept.

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  • british_roverbritish_rover Posts: 8,458
    Any BMW inline six would work but the twin turbo mill from the 335i would be best.
  • fintailfintail Posts: 41,900
    That would be amazing in some vintage BMW or maybe another car as some kind of hybrid. It could be a real sleeper...put that in a Bavaria or something.

    I'm really thinking of the potential of the old M103/104 I6 in a fintail or W108, or maybe a diesel badged W123. It should fit in the hole, add maybe 50hp from the old engines (maybe double the diesel hp), and be quieter and even smoother. The bad thing is that the old engines might actually get better mileage, maybe from the lower displacement.
  • ajvdhajvdh Posts: 223
    A friend of mine who's a long-time BMW mechanic is currently running around in a stock-looking Bavaria with a mildly tweaked 3.8l S38 from a late '80s Euro M6. Admittedly not a V8, but with well north of 300 HP in a car that weighs less than a 1 series, it's a pretty interesting ride.

    This same guy was one of the builders of a late 80s M5 which wound up retaining the "correct" motor, if by "correct" you mean "punched out to 4.0l and running a turbo with 20 psi of boost."

    Speaking of BMW V8 swaps: I see in this months Roundel, somebody's trying to sell an S62 from a 2001 M5. Complete with wiring harness. Pre-war 328 swap, anyone? I can hear Shifty grinding his teeth at the thought.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,579
    I would personally come to your house and dissolve you in a vat of hand lotion if you messed up a pre-war 328. :mad:

    20 PSI of boost? Isn't that asking for KA-BOOM? I trust he's not doing that for long, or up a steep hill. Maybe a big C clamp on the cylinder head?

    A 300 HP Bavaria...the mind boggles.....Hmmm....sounds like lipstick on a pig to me, but you know, I am so mean and opinionated, don't pay me any mind! ;)

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  • texasestexases Posts: 7,762
    "A 300 HP Bavaria...the mind boggles.....Hmmm....sounds like lipstick on a pig to me, but you know, I am so mean and opinionated, don't pay me any mind! "

    Sounds kinda like the high-output 6 european car magazine put in an older 528i - they had lots of trouble getting the chassis to handle all the power.
  • fintailfintail Posts: 41,900
    I think that Bavaria would be pretty cool. An the key is to keep it looking stock, even have it wear the most boring wheels possible. A real sleeper.

    Shifty is right about messing up the prewar car...that's a crime to invoke capital punishment. IIRC the Sbarro replica 328 had a BMW I6, so maybe that would be better - when your original engine was out for servicing but you still wanted to drive it, of course.
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