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Cad 500 Fuel Injection

Discussion in 'The Garage' started by 2High4U, Sep 27, 2006.

  1. 2High4U

    2High4U 1/2 ton status

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    I was wondering if any one had a place to find information on a MPFI (multi port fuel injection) on a 500 Caddy.
    I was looking at affordable fuel injection but im going to need a custom intake manifold and there in lies the problem. If anyone has knowledge of this pm me or post up.

    I dont want tbi if I can help it.

    thanks.
     
  2. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    MPFI on a Caddy is gonna be a good amount of work. Buying an aftermarket TBI setup would be the easiest. However, I'm 99% sure that I saw an aftermarket caddy manifold drilled and tapped for injectors somewhere. I'll do a little digging and see what I can find.

    You can also adapt Ford 460 manifolds to the cadillacs, so if you can find one of those set up for MPFI, you're good to go.
     
  3. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    Can't find the one I was thinking of at the moment. However, Bulldog manifolds have large flats on each runner (I'm guessing from casting) that you could drill and tap with a little work.

    Personally, I'd rather run TBI than go to all that work for a motor where tenths of a second aren't going to matter.
     
  4. BranndonC

    BranndonC 3/4 ton status

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  5. ntsqd

    ntsqd 1/2 ton status

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    MSD sells aluminum injector bosses. They DO NOT have to be welded in, there are epoxies more than up to the job. Miller-Stephenson 907 comes to mind. Drill a simple hole in each runner & epoxy in an injector boss. MSD also sells a cut to fit fuel rail extrusion though I'm told that there are less spendy sources, I just don't know who they are.

    The fancy guys will tell you that the angle of the injector makes a difference, but a friend who's done a bunch of research for his EFI conversion on a 225 Slant 6 (don't ask why 'cause I don't know) has found that the angle mostly matters to cold start emissions.

    The 460 intakes do fit, but they do take some work & welding to seal off the lifter valley and have the bolt holes agree with the intake bolt holes in the heads.
     
  6. grimjaw

    grimjaw 1/2 ton status

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    I thought the '76 Cadillac El Dorado had a option for FI? Does the stock system suck? I know it may be a PITA to find a set up but it may be cheaper.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Some of the Cadillacs were indeed FI, but it was an analog system, and terrible. I believe that was tied into the 8-6-4 system they had all sorts of problems with. Of course, with modern technology they are doing exactly the same thing, but back on track...

    You might be able to utilize the manifold and rails, but no idea where you'd find them, I doubt there are many out there. I know I've never seen one. (wouldn't mind pictures if anyone has them though!)

    Yet another wild idea might be Crossfire injection, if it is somewhat easy to get the crossfire TBI's to bolt up to a Cadillac manifold, but you'd also need a dual carb manifold. The downside of the TBI at that point would be somewhat negated (closer to the valves) and two TBI's flowing somewhere on the order of 1000CFM should be plenty. Just another idea.

    I plan on fuel injecting my Olds at some point, but I think BBC TBI will do the trick, as I just can't see spending that much more money on rails, intake, injectors etc. BBC TBI is an option as well of course, but as the original poster mentioned, he doesn't really want TBI, which is understandable.
     
    Last edited: Sep 28, 2006
  8. mouse

    mouse 1/2 ton status

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    The TBI system used in the mid-70's would be a good place to start. You can modify the distributor to run a SBC TBI small cap internals. Then, use the 90's chevy TBI wiring and computer to control things.

    I've seen the caddy systems, including manifold, on Ebay a couple of times.

    As said, the old systems were finicky, but using it as a basis of a new system might make a conversion easier.
     
  9. Dallin

    Dallin 1/2 ton status

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  10. ntsqd

    ntsqd 1/2 ton status

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    Some of the Cad Sevilles had Olds 403s with that early EFI. Would be a good source for an intake, fuel rails, & TB to EFI an Olds engine. Doubt I'd mess with any of the rest of it.
     

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