75 coupe deville 500 cu in upgrades tips?
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 8 of 8
500, 472, 425, 368 Discussion, 75 coupe deville 500 cu in upgrades tips? in Cadillac Engine Technical Discussion; Anyone out there in caddyland have any tips on upgrading a 75 500 motor? Any performance tips would be greatly ...
  1. #1
    jcunn2d is offline Cadillac Owners Member
    Automobile(s): 1975 Coupe deville
    Join Date
    Jun 2012
    Age
    29
    Posts
    2

    Cool 75 coupe deville 500 cu in upgrades tips?

    Anyone out there in caddyland have any tips on upgrading a 75 500 motor? Any performance tips would be greatly appreciated.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    BRUCE ROE is offline Cadillac Owners Fanatic
    Automobile(s): Eldorado
    Join Date
    Jun 2009
    Posts
    206

    Re: 75 coupe deville 500 cu in upgrades tips?

    1st things are get a replacement timing chain, a good dual exhaust
    (without that terrible cat converter), and convert the trans to switch
    pitch. These will improve economy & performance, a lot. After that
    are dozens of possibilities, which trade off economy, expense, and
    driveability. What do you want? Bruce Roe

  4. #3
    jcunn2d is offline Cadillac Owners Member
    Automobile(s): 1975 Coupe deville
    Join Date
    Jun 2012
    Age
    29
    Posts
    2

    Re: 75 coupe deville 500 cu in upgrades tips?

    I'm looking to get more horsepower without compromising the comforts of a Caddy. Your advice is much appreciated. Thank you!

  5. #4
    cadillac_al is offline Cadillac Owners Connoisseur
    Automobile(s): Cadillac 78 Seville, 78 Coupe de Ville, 92 Sedan de Ville
    Join Date
    Feb 2007
    Location
    Maine
    Age
    52
    Posts
    2,674

    Re: 75 coupe deville 500 cu in upgrades tips?

    That Bruce must be a glutton for punishment lol. I wouldn't pull out a perfectly good engine to change the timing chain unless there was some other reason to pull the engine. It would be a bear to do it in the car imo. Those timing chains are wimpy but they will still run a long time with the plastic off them. I took one out of a Chevy 400 last year with 120k on the clock and all the plastic was still on the cam sprocket!!

    I like the idea of converting to switch pitch. I didn't know you could do that. Can you do that to any th400? Is there a kit for it?

    I would just give the old 500 a good tune up, make sure the secondaries open on the carb and replace the fuel filter, and give it a nice dual exhaust.........and the switch pitch if it is easy.

  6. #5
    BRUCE ROE is offline Cadillac Owners Fanatic
    Automobile(s): Eldorado
    Join Date
    Jun 2009
    Posts
    206

    Re: 75 coupe deville 500 cu in upgrades tips?

    If your car has a TH400 trans, it can be converted to switch pitch. My
    first conversion reduced 0-60 by a whole second, no other changes.
    And everything else was smoother & more responsive, with a slight
    improvement in fuel economy. This requires an electronic switch pitch
    controller to complete the picture. Trans parts are best obtained from
    a 65-67 Buick, Olds, or Cad trans; upgraded torque converters are
    available, as is the controller.

    I saw a request to improve performance of a 75 500. The first step will
    always be, get all periodic maintenance up to date. And that means
    replacing the OEM timing chain. Everyone may do what they want with
    their car. You can chose when to replace the chain, or THE CAR will chose
    when to change it for you (at the side of the road). Drive you car around
    the block, and tow it home when it breaks down. Do what is easy, or do
    what needs to be done. Accept degraded performance, or have it run
    better than new. If it is fuel injected, we are talking preventing a major fire.
    Do your maintenance, and drive it coast to coast. My 77 drove to Canada,
    Florida, California, and New Hampshire in recent times, trouble free.

    I read, improve Cad performance while retaining Cad Comfort: exactly my
    method. My suggestions are a good beginning, no Cad compromises.
    Do these, do all maintenance, then consider more drastic measures.

    I have changed a lot of timing chains without pulling the engine, but
    it's about as easy either way. Pulling an engine isn't a big deal; doing
    an engine overhaul is a big deal.
    good luck, Bruce Roe

  7. #6
    drmenard is offline Cadillac Owners Enthusiast
    Automobile(s): 95 fleetwood 81 deville
    Join Date
    May 2003
    Location
    Massachusetts
    Posts
    953

    Re: 75 coupe deville 500 cu in upgrades tips?

    I agree the Bruce 100%... the timing chain must be changed after all these years.. Its the years that make those chains loose there plastic not the miles..And dont buy a cheap chain, get a good cloyes chain and sprockets.. NOT the cheap $40 set get the $80+ set that you can advance your cam timing 4 degrees..
    Now Bruce... Don't you remember in the late 70's they took out alot of metal out of those TH400 cases and they can't be turned to a switch pitch...Don't know for sure what year they did that , but if I was going to do a switch pitch look for a 75 or earlier case...Or take it apart and look..

  8. #7
    BRUCE ROE is offline Cadillac Owners Fanatic
    Automobile(s): Eldorado
    Join Date
    Jun 2009
    Posts
    206

    Re: 75 coupe deville 500 cu in upgrades tips?

    Quote Originally Posted by drmenard View Post
    I agree the Bruce 100%... the timing chain must be changed after all these years.. Its the years that make those chains loose there plastic not the miles..And dont buy a cheap chain, get a good cloyes chain and sprockets.. NOT the cheap $40 set get the $80+ set that you can advance your cam timing 4 degrees..
    Now Bruce... Don't you remember in the late 70's they took out alot of metal out of those TH400 cases and
    they can't be turned to a switch pitch...Don't know for sure what year they did that , but if I was going to do
    a switch pitch look for a 75 or earlier case...Or take it apart and look..
    Are you saying, all those engines need the cam advanced 4 degrees? Better get that on my list.

    I believe that I was able to convert a '77 TH400 to SWP. Perhaps about 1980 they took out the
    metal for the stator oil passage. But a case swap will take care of that. I heard someone
    figured out how to avoid the issue, by a modification to the pump assembly. But I never
    got the details, or studied it myself. So much to do... Bruce

  9. #8
    drmenard is offline Cadillac Owners Enthusiast
    Automobile(s): 95 fleetwood 81 deville
    Join Date
    May 2003
    Location
    Massachusetts
    Posts
    953

    Re: 75 coupe deville 500 cu in upgrades tips?

    From what I am told that all the stock cams are ground retarted so to have a smooth idle ...so if your running a stock cam best to go with the 4 degrees advanced..

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