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Caddy motor swap info?

Discussion in 'The Garage' started by mikey_d05, Jun 11, 2006.

  1. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    I'm looking for info on swapping a caddy 500 into my truck. Specifically...is there anyone who makes bolt in motor mounts for a 73-87 truck?

    Also, can I use 454 TBI parts to turn it into an EFI motor? I don't think it'll eat THAT much fuel and It'll stay stock or close to it for a while since I'm most likely going to be using an NP205 now and this is gonna cost me quite a bit to do the whole swap.

    I scored a caddy 500 with a matching TH400 for $200 today. It supposedly runs but has a bad coil. Even if it needs some work, $200 for the combo is a damn good deal in my eyes. Also, Branndon, if you read this, you're going to have a PM shortly. :wink1:
     
  2. hack500

    hack500 1/2 ton status

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    using the tbi you'll need to modify the chevy distributor by adding a collar for the hold down to clamp onto. cad on left - chevy right. and add some bigger injectors. most likely you'll need a new prom that'll work with caddy's cam. don't forget a rear sump oil pan.

    cad-chevy-dist.jpg
     
    Last edited: Jun 11, 2006
  3. BranndonC

    BranndonC 3/4 ton status

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    i bought a universal motor mount kit, then trashed it, not worth it for me, too confusing. thats an awesome price. Unfortunately i dont know anything about the tbi. Anytime someone asks me something i dont know about the caddy, I refer them to http://www.cadillacpower.com/forum/
     
  4. diesel4me

    diesel4me 1 ton status Premium Member

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    again??

    Hmm....seems every week someone asks for Caddy swap info...

    One place that does make motor mounts is Maximum Torque Specialties...on the web at www.500cid.com ..but its not that hard to make a caddy engine bolt up with factory eldorado mounts,and a few homebuilt brackets..a site with a truck in progress with pictures can be found at www.geocities.com/bigblockman472/VictimizerRacing_78Chevrollac ..


    You need an Eldorado oil pan or an aftermarket equivilant,with a rear sump,to put the motor in a truck--the usual "front sump" RWD Caddy pans hit the X member under the motor..I've seen guys fudge it,by raising the motor mounts way up so it misses,but it could lead to bad vibrations from driveline angles being too far out of whack...best to change the pan,and the oil pump pickup (different on rear sump)...finding a good used eldorado pan is getting difficult..scarce now,especially up here in rust country..


    The Caddy TH400 has a weird super long tail (most do anyway) and a different spacing on the tranny mount bolt pattern than other GM TH400's,but an adapter plate is easily made..--it will work on a 2WD truck as is,with a shorter driveshaft and some u-joint fudging..but to mate it to a GM 4x4,you'll need to ditch the long tailshaft and housing,and install a 4x4 TH400 output shaft ,and use the apprpropriate TH400 adapter to whatever T case your runing....or you can buy an adapter that lets the Caddy engine bolt up to the existing Chevy tranny already in your truck..

    I hear the oil filter sometimes hits the front X member on some years..a 425 one has a better angle,and bolts to a 472/500..or a shorter filter could probably be found,IF its a problem..the exhaust is a near match,Caddy manifolds dump in the same spot practically as a Chevy motor,so only minor tweaking makes your old exhaust fit..

    I have no clue about adding TBI,bit I'm sure its been done..I've seen a 500 in good tune get 16-18 mpg on road trip--we used to go to New England Dragway and back,in the Coupe Deville convertible the 500 I have came from,
    a 175 mile ride,on a half tank of gas....at 80 mph!...

    There is lots of info on the web about swapping a Caddy motor into just about anything..even found a site with a VW BEETLE with a 500 in it!:eek1:

    I have a 76 500 and TH400 from a CoupeDeville in my shed out back..been there 5+ years,waiting for me to make up my mind what to do with it..sat in my friends shop a few years after he pulled it from the car(it was his) when it got too rotted to trust driving it anymore..with todays gas prices its doubtful I'll ever use it,and now that I see 200 bucks will buy one now,I guess selling it wont bring much $$$$...:( ..

    I'd like to see someone put it to good use..I paid 500 bucks for it back then,because it ran great before we yanked it--we drove all over hell in that caddy..not sure how it would run now,but I turn it over by hand and it still feels like everything is free,no stuck valves yet....sigh..maybe someday I'll be rich enough to hear it run again..
     
  5. BoondocK5

    BoondocK5 1 ton status Author

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    same here, Iv'e still got my 500 all pulled a part and waiting, with 1k in machine work into it and needing new parts to complete it it'll probably just wait till I get a 34, 5 window kit, to put it in, back to the venerable 350
     
  6. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    I figured I'd need to buy a 454 throttle body and have a custom prom burned, but you're saying that with the proper mods I can use 454 TBI parts to fuel this sucker correct?
     
  7. hack500

    hack500 1/2 ton status

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    yep, you'd also need the tbi->manifold adapter(4bbl spreadbore) that the early tbi 454's used. in addition to the various sensors needed but it can be done.
     
  8. mike n

    mike n 1/2 ton status

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    We did a Caddy swap about 10 years ago into a 77 K5.

    The donor 500 came from a 71 Eldo convertible, and iirc we used the stock Eldo motor mount bracket and fabbed our own custom crossmember to fit.

    We didn't inject ours, we used a Q-jet atop an Edelbrock Performer intake, so I can't answer any EFI questions you may have.
     
  9. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    I counted on needing the adaptor but figured it was some funky one that I'd just have to have machined.

    What all sensors do I need and how big of a pain is it to retrofit them to a Caddy block? My TBI wiring diagram is buried somewhere in my garage at the moment with little hope of being found without a shovel.

    The TC lockup stuff is gonna have to be taken out since this is a 400, how about the EGR and knock sensor? I don't think this will be that big of a chore, but it's gonna require some pretty big cash being thrown at it.
     
  10. ryan22re

    ryan22re 1/2 ton status

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    I'm guessing a custom chip could remove all of those functions from the ECU. Did the 454's use a knock sensor? I am thinking no, but could be wrong. I'm guessing most of the sensors from your 350 would work just fine on the 500, just have to put them in the right (or similar) spot.
     
  11. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    I'll get a pitchfork and dig out my manual tomorrow. I can get a custom chip that'll delete knock, egr, and TC lockup, but if they're already on the motor or easily swappable I might as well use them.

    I know there are quite a few caddy swaps around, but I couldn't dig one up that is using BBC TBI, hence all of the questions.

    Thanks for all the help so far everyone.
     
  12. diesel4me

    diesel4me 1 ton status Premium Member

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    the "F" word....

    I've seen photos online of 472 and 500 Caddy motors with a FORD 460 intake manifold on them!..believe it or not,I guess the Ford intake is pretty close to the caddy one,and bolts up with some modifications..not sure if a 460 fuel injection setup would work...???--It'd be a lot of work I bet...:crazy:
     
  13. mike n

    mike n 1/2 ton status

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    You'd be better off with the Ebelbrock Performer intake that's made for the Caddy than trying to rig a F**d intake on there. The Eddy would probably be cheaper than some half baked F**d intake and adapters would be.

    Edelbrock released that intake just as we were finishing up our project, so we had a chance to back-to-back it with a stock aluminum Caddy intake, and the performance gains with the Eddy were huge.
     
  14. 3 on the tree

    3 on the tree 1/2 ton status

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    FYI, Caddie did put TBI 500s in the last of the Eldo convertibles, so all the sensors for a Caddy motor should be available.
     
  15. hack500

    hack500 1/2 ton status

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    yeah there were FI'd 500's in '76.... though it wasn't tbi-type - caddy FI had one injector per cylinder.

    however, I seem to recall some caddy enthusiasts complaing (and searching for) that some of the required parts have been discontinued. '76 FI cars seem pretty rare.
     
  16. stkcode

    stkcode Registered Member

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    The knock sensor depends on the year. So in short, yep.
     

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