I just picked up a complete parts truck (5.7 vortec 1996 Silverado) after deciding not to do an LS swap. Long story short, from some info I gathered, I thought it would be a somewhat straight forward swap. The info I’m coming across now is FI to carb and a lot of the other detailed threads are old. I’m struggling to get clear info on this swap. I’m looking for info on what I’ll need to do to complete the job keeping a fuel injected system.

I thought: swap front accessories, oil pans were the same, upgrade headers, motor mounts are the same, wiring harness would be the same and just use the ecm from the 5.7. Do I have to use my intake, use vortec fuel injectors and upgrade TB? Will my wiring harness from the car plug into the 5.7 ecm?

should I have just done a 5.3? Ha. I thought this would be more of a drop and go kind of thing.

 

Is it even worth it?

 

Best thing to do would be: use the newer motor, AS IS (NOT "rebuild" it except for a valve job) up to the heads; ditch the intake and spider and all that; put your accessories and oil pan on it; get a 4-bbl intake for Vortec such as Performer RPM, and a 4-bbl <-> TBI adapter; and put your existing EFI system back on it, as-is. (well, almost...) You'll want the injectors from a TBI 350 such as out of a Caprice or truck, the ESC and knock sensor for a 350, and the 350 chip. All of that can come from one junk vehicle. You'll want tuning as well, GUARANTEED. Might want to look into EBL for that.

You'll benefit from a better cam than the one that comes in those truck motors. I'd suggest a Comp XR264HR or XR270HR (depending on your intended use etc.), which will ABSOLUTELY REQUIRE replacing the valve springs. For that I'd recommend LS6 ones such as from Texas Speed or ws6store, and the Comp "adapter" retainers 787, with all the appropriate hardware. Set them up to some consistent height slightly below 1.800", such as 1.780". Headers of course (I'd recommend Dyno Don's), a good cat, and a good cat-back of your choice such as the Hooker one.

That's a 360 - 375 HP recipe right there depending on which cam you choose.

 

I totally agree.

Headman 1 5/8" Headers, an Edelbrock Performer or Performer Air-Gap (NO Performer-RPM) Manifold and Carb...
are good for 300+ HP with a good running Stock Vortec-350.

It is very easy to build from there to 450 or 500 HP with that engine.