Engine swap question

Tiny
PIATKOWSKI000
  • MEMBER
  • 1979 CADILLAC SEVILLE
  • 5.7L
  • V8
  • FWD
  • AUTOMATIC
  • 30,000 MILES
Hello. Will the engine from 1977 Cadillac Seville 5, 7 Gas will fit to 1979 Cadillac Seville or do I have trouble with this change? Both cars had the same 5.7 V8 engine. Someone made changes in my car listed above and took off all fuel injectors system, exhaust system and put carburetor in this car. I would like to bring back car to original shape. I have all original fuel injectors and electric wires in my second 1977 Seville. Do I have trouble with this change or is it should fit? I will be very very thankful for help. I am from Poland so sorry for my english. Thank You.
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Tuesday, January 3rd, 2017 AT 2:02 PM

12 Replies

Tiny
STEVE W.
  • MECHANIC
  • 13,973 POSTS
Same parts and injection hardware for both years, GM did not change much until 1980 when the newer smaller version came out (with that ugly lump of a trunk).

That is actually an Oldsmobile engine in both. Cadillac did not have a "small" engine for the car so they simply "borrowed" from the sister company and dressed it as theirs.
1977 to 1979 also have disc brakes and better ride than the 1975/1976 versions.

You have a big job ahead of you, good luck.
Nice cars, wish they still looked that good in my area, around here those would be scrap by now.

Your English is better than many of the people I talk to daily, and they were born speaking "english".
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Tuesday, January 3rd, 2017 AT 7:43 PM
Tiny
PIATKOWSKI000
  • MEMBER
  • 64 POSTS
Thank You very much for the quick answer. So is it possible to change engines and still have good riding car? I would like to keep this 19 79 Seville in original shape because it is limited version 1 of 200. I have all new fuel injectors in 1977 Seville engine and it sounds well and better than engine from 1979. Thank you.
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Wednesday, January 4th, 2017 AT 5:54 AM
Tiny
PIATKOWSKI000
  • MEMBER
  • 64 POSTS
Will all electric wires fit too? Thank you very much.
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Wednesday, January 4th, 2017 AT 5:59 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,973 POSTS
Everything should be a direct bolt on. Engines are the same, wiring should be all the same.
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Wednesday, January 4th, 2017 AT 6:18 AM
Tiny
PIATKOWSKI000
  • MEMBER
  • 64 POSTS
Thank you very very much. Best regards from Poland!
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Wednesday, January 4th, 2017 AT 6:27 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,973 POSTS
You are very welcome. Thank you for using 2CarPros. Com. Please return with any auto related questions, we are here to help.
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Wednesday, January 4th, 2017 AT 9:44 AM
Tiny
RENEE L
  • ADMIN
  • 1,260 POSTS
Great information Steve W.
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Wednesday, January 4th, 2017 AT 2:10 PM
Tiny
PIATKOWSKI000
  • MEMBER
  • 64 POSTS
Hello again Steve. I have one more question about my problem with 77 and 79 Cadillacs Seville. In 79 Seville they take off all wires from fuel injection and put new edelbrock carburetor. My question is: If I would like to change engine from 77 to 79 seville do I have to make any modification with dashboard wires or all wires from engine and fuel injection are ending in engine bay? Is dashboard wires are separate from the engine and fuel injection wires in engine bay? I hope You understand me. It's really important. I hope You can help me. Thank You very very much.
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Monday, January 9th, 2017 AT 6:34 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,973 POSTS
There is a large connector that joins the interior wiring to the engine and front end wiring mounted at the firewall below the steering shaft. You should be able to take the entire front harness from the 77 and plug it in and get all the wiring they removed back.
There will be a bolt that holds the two big connectors together.
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Monday, January 9th, 2017 AT 9:53 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,973 POSTS
These are similar to the connector except yours will have more wires.
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Monday, January 9th, 2017 AT 2:41 PM
Tiny
PIATKOWSKI000
  • MEMBER
  • 64 POSTS
Thank You very very much for help. Now I know much more. I hope everything will be ok and car will still be riding. The engine from 77 sounds much better than engine from 79. I like to keep old cars in original shape. Thank You very much again for help.
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Monday, January 9th, 2017 AT 4:50 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,088 POSTS
Please use 2CarPros anytime, we are here to help and tell a friend.

Best, Ken
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Saturday, January 14th, 2017 AT 11:23 PM

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