90 Brougham Motor Swap: LT1 or 455 Rocket
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 9 of 9
5.0 and 5.7 Discussion, 90 Brougham Motor Swap: LT1 or 455 Rocket in Cadillac Engine Technical Discussion; For all owners of 86-90 Cadillac Broughams, we all know that the 5.slow L is the worst engine Cadillac has ...
  1. #1
    MadCaddie69's Avatar
    MadCaddie69 is offline Cadillac Owners Fanatic
    Automobile(s): 1990 Cadillac Brougham, My mom's 2001 Cadillac Deville DTS
    Join Date
    Aug 2007
    Location
    Jessup, MD
    Posts
    113

    90 Brougham Motor Swap: LT1 or 455 Rocket


    For all owners of 86-90 Cadillac Broughams, we all know that the 5.slow L is the worst engine Cadillac has ever used. I know a lot of people out there have considered swapping the motor out for bigger motors. I own a 1990 Cadillac Brougham and I want to do a unique motor swap. I'm thinking about using an LT1 straight from a 95-96 Corvette. But lately, I've been looking up on Olds/Pontiac/Buick 455. This motor has a lot of potential and is a LOT cheaper than the LT1. The LT1 in a 1990 Brougham is pretty unique to me because no one's done it. Of course, the initial thought is to buy a 95-95 Fleetwood, which is the car I've always wanted(still want it!!), but I also like the sound and power of old school muscle. The car is kinda in between old school and new school. Any suggestions?

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    96Fleetwood's Avatar
    96Fleetwood is offline Auto Enthusiast
    Automobile(s): 2002 Eldorado Collectors Series and 1994 Fleetwood
    Join Date
    Jul 2005
    Location
    Naperville, IL
    Age
    34
    Posts
    3,684

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    455 is a great motor, but is $$$ if you find one that is in good shape. My father has a stage II 455 in his '70 Electra Convertible and it is a great torque monster.

    It depends if you want to deal with a carb'd motor again.

    The most economical solution would be to do a 350 TPI swap like Destroyer did on his 1991 Fleetwood. You might be able to find a 355/383 TPI for cheap?

    I give you props for this idea, I have always wanted to do a LT1 in a '90-92, but never had the time. Go for it!!
    1994 Cadillac Fleetwood- the sleeper project
    2002 Pontiac Trans Am Collectors Edition WS6 Conv't- the show car
    2002 Cadillac Eldorado Collectors Series # 1572
    2006 Mini Cooper S BRG 6spd- the autox gokart
    2014 Range Rover Sport V8 Supercharged- wife's daily driver
    2014 Ram 1500 Laramie Hemi Crew 4x4- daily driver/tow vehicle

  4. #3
    N0DIH's Avatar
    N0DIH is offline Cadillac Owners Master
    Automobile(s): 94 Fleetwood Brougham
    Join Date
    Aug 2004
    Location
    Rockford, IL
    Age
    47
    Posts
    7,490

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    I love BB's, but they are pricey, in the initial cost and fuel dept. The LT1 is a great engine and can be easily found for $300-$500. I picked up a whole parts car for $300 with 4L60E and LT1, disc rear end and 12" front brakes. I call that a killer score. The LT1 tuned will do well in that car and a sweet swap. I would lean that way instead of going old school. But, if you go old school, by all means, fuel inject it!!!

    And a BBO will trash any trans you put in it short of a 4L80E or THM400/3L80. So hands down, $$ is the LT1.

  5. #4
    MadCaddie69's Avatar
    MadCaddie69 is offline Cadillac Owners Fanatic
    Automobile(s): 1990 Cadillac Brougham, My mom's 2001 Cadillac Deville DTS
    Join Date
    Aug 2007
    Location
    Jessup, MD
    Posts
    113

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    That's what's up. I'll get my money right and keep my eyes open.

  6. #5
    joe_padavano is offline Cadillac Owners Member
    Automobile(s): 93 Allante
    Join Date
    Mar 2006
    Location
    Northern Virginia
    Posts
    78

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    First of all, the Olds, Buick, and Pontiac 455s are three completely different motors. The only thing they share is the bellhousing bolt pattern and the distributor cap. The Olds will bolt in using the 307 motor mounts; the others require custom mounts. Any of the three will shred a stock 200-4R transmission, though this trans can be built to withstand the torque. The least expensive way to do this is to find a running but rusted full size Olds from the 1970s. Cars like this can be had for $200-500. Another choice is an Olds 403. This is a small block and is externally identical to the 307.

  7. #6
    N0DIH's Avatar
    N0DIH is offline Cadillac Owners Master
    Automobile(s): 94 Fleetwood Brougham
    Join Date
    Aug 2004
    Location
    Rockford, IL
    Age
    47
    Posts
    7,490

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    Yup, but those later year 200 4R's were dual bolt pattern, so shouldn't be a bolt up issue. But the trans destruction when you nail the gas the first time has to be addressed....

    Olds is my BB of choice there for ease. Pontiac is my preferred 455, but the Buick is very fun too (largest bore, shortest stroke, revs like crazy). Pontiacs are my overall favorite.... Diesel like torque and can move freight trains if needed....

  8. #7
    MadCaddie69's Avatar
    MadCaddie69 is offline Cadillac Owners Fanatic
    Automobile(s): 1990 Cadillac Brougham, My mom's 2001 Cadillac Deville DTS
    Join Date
    Aug 2007
    Location
    Jessup, MD
    Posts
    113

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    I found an LT1 at the junkyard right around the corner from my house! And it's cheap! Now I gotta find a 4L60E tranny to match it. Now I need to know what issues I will face to do this swap. Preferrably wiring issues. Any tips?

  9. #8
    N0DIH's Avatar
    N0DIH is offline Cadillac Owners Master
    Automobile(s): 94 Fleetwood Brougham
    Join Date
    Aug 2004
    Location
    Rockford, IL
    Age
    47
    Posts
    7,490

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    93 was last year for 4L60 (not E) in cars and 4 bolt tail
    94 was 4L60E, without PWM TCC modulation and 4 bolt tail (can add PWM solenoid if you so desire)
    95 was first year PWM and 4 bolt tail (can remove and plug PWM solenoid if you so desire)
    96 has removeable bell housing and 6 bolt tail section

    Make sure you run appropriate PCM tune for the trans you have, make sure the tuner knows exactly which you have!

    A truck 4L60E might be a decent one, they are probably rebuilt more often. I just pulled one from a 95 cop car that has been rebuilt, but I still have no idea if it is good or not (painted a very light green even...). The Suburban ones will have the HD parts similar to a V4P tow package car, so if you want a drop in one that should be robust, that is a good choice. And Suburbans from 96-99 ALL came with either 3.42's and 3.73's. 4.10's only on 3/4t and then they got 4L80E's. You can also get any truck trans from 96-present, 4L60E or 4L65E, doesn't matter, they all work fine.

    Talk to Shane at CPT about the differences and what is a good core if you are gonna rebuild one.

  10. #9
    mparker1nt is offline Cadillac Owners Member
    Join Date
    Apr 2012
    Posts
    3

    Re: 90 Brougham Motor Swap: LT1 or 455 Rocket

    Did you get it done?

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting