engine swap from 5.7 to 5.7 vortec

1994 GMC SUBURBAN
Avatar
EHURLEY88
  • MEMBER
  • 1 POST
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
Feb 16, 2010 at 4:30 PM
Advertisement
Avatar
2CARPRO JACK
  • CERTIFIED EXPERT
  • 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.
Feb 17, 2010 at 7:47 AM
Avatar
ATWDIWDW
  • MEMBER
  • 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?
Aug 19, 2017 at 12:01 PM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,855 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

Aug 20, 2017 at 12:08 PM
Avatar
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?
Aug 21, 2017 at 5:40 AM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,855 POSTS
Not that I am aware of, you will need to take it apart and look.
Aug 21, 2017 at 11:39 AM