67 Cadillac Eldorado 429 to a 425

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds

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 3 of 3
500, 472, 425, 368 Discussion, 67 Cadillac Eldorado 429 to a 425 in Cadillac Engine Discussion; I have a 67 Eldorado, the Motor is ok, but will cost a lot to buy a new/rebuilt motor. I ...
  1. #1
    Jmikestlmo is offline Cadillac Owners Member
    Automobile(s): 67 Eldorado
    Join Date
    Mar 2011

    67 Cadillac Eldorado 429 to a 425

    I have a 67 Eldorado, the Motor is ok, but will cost a lot to buy a new/rebuilt motor. I found a 425 rebuilt motor, would this fit into my car? would this be a mistake to swap it to the 425? The 425 is still a 7.0, but the 429 does not have any upgrade parts for it, I put Fuel injection on it and it runs better, but I want to make it more of a pleasure to drive with easier parts to find. Anyone have any thoughts? I know some of you will think I am crazy to want to do this, but the 429 is so hard to find parts for and mostly year specific , Please help with ideas if it will drop in and can I use my Original Transmission.

  2. Remove Advertisements

  3. #2
    deVille33 is offline Cadillac Owners Connoisseur
    Automobile(s): 1977 Coupe (blue), 1977 Coupe (yellow), 1977 Coupe (green)
    Join Date
    Mar 2006
    Western Massachusetts

    Re: 67 Cadillac Eldorado 429 to a 425

    From other posts here, the 429 and the 425 did not share the same transmission mounting pattern, so you will need a TH400 or an adaptor to put that 425 in your car. You will find that there are few options for your 425 engine either, except carburetor / fuel injection.

  4. #3
    BRUCE ROE is offline Cadillac Owners Fanatic
    Automobile(s): Eldorado
    Join Date
    Jun 2009

    Re: 67 Cadillac Eldorado 429 to a 425

    My experience is, redrilling 2 trans hole for the engine bolts will let the 425 BOP engine bolt to the 67 trans, no adapter plate. You'll need the right oil pan, exhaust manifolds, misc. Bruce Roe CLC # 14630

  5. Remove Advertisements
    Cadillac Forums

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

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

Please enter a valid email address for yourself.

What Cadillac(s) do you own? (Or type NONE)

Please select your insurance company (Optional)

Your date of birth and age are displayed in several places on the forum. Only the administrator will have access to your date of birth should you choose to hide it via the privacy option below.


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.


Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts