1986 Fleetwood Brougham engine swap
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RWD 19xx-1984 DeVille and Fleetwood,
1985-1996 Fleetwood and Brougham Forum Discussion, 1986 Fleetwood Brougham engine swap in Past Cadillac Vehicle Discussion; hey guys im a new member here, I have a 2006 DTS performance and I just bought a 1986 Fleetwood ...
  1. #1
    caddytat is offline Cadillac Owners Member
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    1986 Fleetwood Brougham engine swap

    hey guys im a new member here, I have a 2006 DTS performance and I just bought a 1986 Fleetwood Brougham with the 5.0. I really want to put in a bigger engine for a little more power. What would be the easiest, most reliabe engine to put in it? (350, 403)

    thanks alot
    andy

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    outsider is online now Cadillac Owners Connoisseur
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    Re: 1986 Fleetwood Brougham engine swap

    350 seems to be most common on them since it was an option (tow package i think)

  4. #3
    jayoldschool's Avatar
    jayoldschool is offline GM RWD V8 addict
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    Re: 1986 Fleetwood Brougham engine swap

    The 350 that was an option in 90-92 was a Chevy 350, not Olds.

    So, a straight bolt in, using all your accessories would be anything from the Olds family. 350, 403, 455. There are a couple threads around here where others have swapped in the the Olds 350.

  5. #4
    caddytat is offline Cadillac Owners Member
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    Re: 1986 Fleetwood Brougham engine swap

    Thanks for the replies....I will have to do a search (I know prob should have done that in the first place but I'm lazy). Is there significantly more power in say the 455 or 403 than the 350 to make it worth it. Also out of the three sizes which one is most reliable. Thanks.

  6. #5
    cadillac kevin's Avatar
    cadillac kevin is offline Cadillac Owners Master
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    Re: 1986 Fleetwood Brougham engine swap

    any of them are reliable. they're all well built. the pre '73 455 will give you the most power (about 370-400 hp and 500+ ft/ lbs of torque)
    the pre 73 350 will give you 300 hp and 350 ft/lbs of torque.
    both will require swapping your transmission for one that can handle more powr (turbo 350 for the 350, turbo 400 for the 455)
    the 403 is kind of weak on power (200 hp IIRC), although with enough budget it can become one hell of a high power motor.

  7. #6
    csbuckn is offline Cadillac Owners Master
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    Re: 1986 Fleetwood Brougham engine swap

    I'm starting to think that a simple swap of the carb would be a huge difference. If you have a carb, put it on without all the emissions stuff. I think you would have to change the dizzy also.

  8. #7
    cadillac kevin's Avatar
    cadillac kevin is offline Cadillac Owners Master
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    Re: 1986 Fleetwood Brougham engine swap

    the CCC carb isnt the problem (although it could benifit from a better than factory tune).
    the problem lies in crappy head design (swirl port), a wimpy camshaft, and a junky intake. by upgrading those 3 things, its possible to go from about 140 hp to 200hp.

  9. #8
    csbuckn is offline Cadillac Owners Master
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    Re: 1986 Fleetwood Brougham engine swap

    Well, I put together an Olds 350 with a RV/Torque cam, 77 heads and an iron intake.....put all CCC stuff back on and it felt pretty much the same. I think the CC carb is the biggest factor in this motor.

  10. #9
    sven914 is offline Cadillac Owners Connoisseur
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    Re: 1986 Fleetwood Brougham engine swap

    Quote Originally Posted by cadillac kevin View Post
    the CCC carb isnt the problem (although it could benifit from a better than factory tune).
    the problem lies in crappy head design (swirl port), a wimpy camshaft, and a junky intake. by upgrading those 3 things, its possible to go from about 140 hp to 200hp.
    That's my plan; 350 heads and intake, and a 403 carburettor. With all that, you can't do any worse than the VIN 9 307 (180hp).

  11. #10
    N0DIH's Avatar
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    Re: 1986 Fleetwood Brougham engine swap

    Weight out the costs, go look at a 5.3L with 50k miles or so on it from the boneyard. I have seen some for as low as $300. Grab the trans too. You get a modern drivetrain for far less than you can build an old school engine from scratch.

    Hence why my LT1 in the garage just sits....

  12. #11
    caddytat is offline Cadillac Owners Member
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    Re: 1986 Fleetwood Brougham engine swap

    well i found an olds 403 pretty cheap....a mechanic buddy told me if I put a better shift kit in the stock tranny it should be able to handle the power. Is that true? also what carb setup should I go for? thanks again for all the help

  13. #12
    sven914 is offline Cadillac Owners Connoisseur
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    Re: 1986 Fleetwood Brougham engine swap

    I wouldn't trust it. The stock transmission is pretty weak, and the 403 will put out a lot of power. I would get a Chevy TH700 transmission, which is more durable, and you will still have overdrive.

  14. #13
    ChatWithaNinja is offline Cadillac Owners Member
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    Re: 1986 Fleetwood Brougham engine swap

    And for my first post ever:

    What kind of labor and fabrication does a TH700 transmission require?
    I ask because I am looking into the same thing with my 86 FWB (and my name is also Andy. Odd eh?).
    Right now I am looking for a good used 350 - non-web mains, so pre 77, right? ACtually, when reading this site, they say that the webbed mains won't really be a hindrance as I am not looking for super power, just a good reliable block with more than the 140 the car came with. http://oldsjunction.classicoldsmobil...ks 1964 - 1990
    And here is a link for the OP on the 403 VS the 350
    http://oldsjunction.classicoldsmobil...st Small Block

  15. #14
    sven914 is offline Cadillac Owners Connoisseur
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    Re: 1986 Fleetwood Brougham engine swap

    The driveshaft would need to be custom fitted (you can get one from a '90-92 Brougham with the 350, but it may not fit right with the Olds motor), and the support beam under the transmission needs to be moved. The TH700 should have a universal (BOP) bell-housing, so you don't need an adapter.

  16. #15
    jayoldschool's Avatar
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    Re: 1986 Fleetwood Brougham engine swap

    TH700R4 does not have the dual pattern bell housing like the TH200-4R. You will need an adapter plate (BOP to Chev) to mount the trans. Available from Jegs, Summit, etc.

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