Engine swap from 5.7 to 5.7 vortec

EHURLEY88

MEMBER
1994 GMC SUBURBAN

Engine Mechanical problem V8 Two Wheel Drive Automatic 175000 miles

i am in the process of trying to swap out a original 5.7 engine in my truck to a 5.7 vortec but im not sure what I need for the change I kno thaat the bolt pattern will match but what do I need from the vortec. Wiring harness andd computer? Im not sure

5 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

The big thing with those is the intake manifold, be sure the bolts are the same. The TBI unit (94) has more vertical bolts in the center 4, you need to be sure the vortec has the same thing. Other than that, the coolant senders in the heads, be sure there are the correct holes for your old sensors to go back into. Beyond that youshould be able to bolt everything else onto the vortec from your TBI. In 94 some of the engines were already vortecs that had TBI, so I dont htink you will have any problems.

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Wednesday, February 17th, 2010 AT 7:47 AM

ATWDIWDW

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4 POSTS

8/19/2017, I have a 1994 suburban 4x4 that I am very attached to. I have a 1999 suburban that I'm not. I would like to put the vortec into my 94, and would if I knew all instruments and trans would be no problem. Sounds like you did similar thing I would like to do.
How did that turn out?

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Saturday, August 19th, 2017 AT 12:01 PM

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

The big thing is you will need to take the wiring harness from the newer one and fit it to the older car. I would change the transmission and exhaust as well.

Also the fuel pump is different in the tank I am pretty sure so it will be a labor of love which it sounds like you have :)

I will help you in every step so please ask any questions and post pictures as you go.

Please let us know what happens.

Cheers, Ken

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Sunday, August 20th, 2017 AT 12:08 PM

ATWDIWDW

MEMBER
4 POSTS

I have looked at both engines, my 94 appears to have what I would call a regular intake, my 99 appears to have a two piece intake.
With out taking things apart is there a way to verify that my 94 is not a vortec block?

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Monday, August 21st, 2017 AT 5:40 AM

KEN L