[Bobbydnovaman]

My 98 k1500 350 vortec 4l60 suburban just spun a main bearing. I've seen this topic before on many sites but it always goes cold with people arguing about its a bad swap or do a LS swap instead and never answer the guys questions. I have a 454 vortec with 18k miles on it with 4l80 and its free. I know the mechanical end is plug and play for the most part aside from maybe the trans cross member and having to buy a conversion output shaft to fit my t-case. I know the computers are the same with different cals. I have the 454 complete with harness and computer so a full swap is fine if i need to. Both engines are MPFI my only question is how easy is the electrical swap. I have heard that the routing of the wires is different in the BB then the SB. with the BB there's more wires that come through the passenger side fires wall as appose to the drivers side. Is this true? and witch ones. also will I have to change the dash harnness to make my gauges work. should I grab the newer cluster too from the BB. I'm Good with electrical just don't know exactly what to change. I've even pulled up schematics and the wiring looks the same. I just keep hearing the routing is different. Can some one who has done this swap please help me out.

[gearheadslife]

I know this isn't really what you are going to want to hear.. but here it goes..

IF IT WAS ME

I'd sell that 18k mile bigblock and 4l80e complete for 35-4000.oo

then get a g.m. crate 96-02 350 vortec 350 and drop it in..
the g.m. engine all new is 2000.00 and will be plug and play..
that 454 drivetrain will not..
and depending on your laws in your area.. the swap most likely requires ALL THE EMMISSION equipment the 454 truck had.. ..

I know you didn't want to hear it..
but if you're hell bent on installing the 454 I'd go look at a truck with one in it. and take note of the wires and where they go..
good luck

[Bobbydnovaman]

Live in michigan no one here cares about emmisions. I am pretty hell bent on 454 vortec cause i wanna mod it later in life. I really want to stay with computer controlled for dd application. I have access to a tech to and a vin licenced programmer to shut off rear o2's.
This is an arizona truck so its spotless besides paint faid.6" procomp lift. I've already put in a 14 bolt SF. And replaced every wearable component in the drivetrain except trans and engine. Its got a 42 gal tank and i only live 4in miles from work. I want the 454 to tow my 73 nova to the track. I usually drive it but its always risky if i break. Thanks gor the input tho.

[hcompton]

You can find a wire routing and replacing proceedure in the oem shop manual. Its a lot of work. I would do a connector count and see if they are the same color and fit. If so you may be able to run any wires you need. But if some of the wires are crossed in the factory harness will trip you up. Replacing the entire harness is the way to go. But will require careful planning and lots of tome making sure every thing goes right where the factory says it needs to go. Try not to cut and peice it back together it never last and always causes problems. I would really try to avoid unwrapping or modifing the harnes as little as possible.

Dont forget the trans harness and computer if its seperate for the ecu. If they are intergrated and the trans are different. It could be wired differently for different trans packages. Careful to color trace everything if mixing harness.

The factory oem manual will help alot.

Factory ecus can and usally are wired differently internally for major model changes. The new mecal may not be the only changes for running the orginal ecu.

[Bobbydnovaman]

I have the entire harness at hand trans included. Should i grab the dash harness as well? Or is that debatable. I would def prefer to not cut and splice. I was already going to grab the ecm from the doner. Do i have to use the newer cluster to make my gauges work seeing as mine is electrical with a roll style odometer the new one is electrical with digital odometer. Where do i find a gm oem service manual?

[gearheadslife]

if 454 is from a different year, you'll need 2 service manuals sets..

my 2004 set is 5 books each 4-5" thick..
helm.com
they printed the oem manuals..