LQ9/4 Swap Questions

[Sierra_1500]

So I've got a project like most people on here who swap a LQ engine into one of the OBS trucks. The only difference is I am starting a little differently than most because I have a 4.3 vortec under the hood. I just mainly would like to know what kind of things I will have to do to make a swap like that work, and I am not sure what to do transmission wise with the truck as it already has a 4L60E in it. Would I need to do most of the actions involved in doing a 5.7 swap but slightly different? The black box computer in it will have to be programmed differently for a v8 or would I just need a whole new one in general? With the wiring would it be best just to get a completely new harness for the truck since the harness is meant for the v6?

There are more specific things with the engine I have questions about, such as what is recommended to put in the engine as far as internals. Ideally I would like to do e-fans but that might have to wait until after the engine is in.

I have been looking for quite a while and I am having trouble finding all of the answers I need before starting a swap like this.

 

[capricefrk013]

So I've got a project like most people on here who swap a LQ engine into one of the OBS trucks. The only difference is I am starting a little differently than most because I have a 4.3 vortec under the hood. I just mainly would like to know what kind of things I will have to do to make a swap like that work, and I am not sure what to do transmission wise with the truck as it already has a 4L60E in it. Would I need to do most of the actions involved in doing a 5.7 swap but slightly different? The black box computer in it will have to be programmed differently for a v8 or would I just need a whole new one in general? With the wiring would it be best just to get a completely new harness for the truck since the harness is meant for the v6?

There are more specific things with the engine I have questions about, such as what is recommended to put in the engine as far as internals. Ideally I would like to do e-fans but that might have to wait until after the engine is in.

I have been looking for quite a while and I am having trouble finding all of the answers I need before starting a swap like this.

Your best bet is to do some searching on ls1truck.com.

But...there really isnt much difference between starting with a 4.3 or 5.7.

The black box ECU can not run an LS. You need the wire harness and ECU from the donor vehicle as well as the gas pedal and TAC module and wiring if it is a DBW. If it is a DBC motor then your stock gas pedal and cable will work.

My LQ4 is bone stock internal wise and I love it. I am building a 5.3 for my Sonoma right now that will be cammed and carbed with nitrous.

I did the e-fans before I even started my swap. The best thing I ever did aside from the LQ4 swap.

 

[skylark]

The V6 frame mounts are different from the V8. You will want to swap them and then use a 1" setback LS adapter mount to keep the tranny in the same position.