wassup people. I have an issue I can't seem to get an answer on. I own a 95 chevy 1500 4x4 5 speed, that had a 5.7 tbi in it. Now I want to install a 95 lt1 that is now a 383 lt1. I want to put this engine into my truck and still use the fuel injection and keep the manual 4x4 tranny. Is this possible?, and what kind of wiring harness is necessary to do so. Also, the ecm with the motor came out of a automatic car. Will I need to use one that came out of a manual car? Thanks for whoever can solve this for me.

 

This swap is doable, but will still need patience and planning. The lt1 is basically a sbc with updates so it will bolt right in place. You will need a radiator specific to the lt1. The fuel system is different, so you will need a fuel pump to feed the 383. The pcm will need to be from a manual, as well as the wiring harness. You will need a exhaust system from a lt1 if you are keeping it smog legal. Don't forget to hook up the cross over lines at the back of the heads. I'm sure there is more but this is a good starting place.

tia

andy schuck

 

nope, you dont have to switch pcms or wiring harness's. reuse whatever wiring harness you have for the LT1. you just need to change the speedo connector proba bly. get ahold of madz28. he does awesome mail order tunes, but for max gas mileage and HP, get a dynotune when the thing is all together and running again. you can use any sbc headers, or the stock mann.s if you wish to. but if mannifolds I'd go with stock LT1 mannifolds if they'll fit the chassis.

more work to hook up the factory gauges though. just a matter of traceing down the ckts of the two diff harness' and mateing them together. aftermarket harness might be alot easier. check out summit racing.

 

I am not worried about the smog issue. I have a custom set of headers fit for the motor and truck. I already have a holley blue electric fuel pump to feed the beast. My main concern is choosing the correct wiring harness for the manual tranny, the correct pcm, ( wich sux because i already have one calibrated to fit the engine specs, and getting the fuel injection to work. Also, how much trouble is it going to be to wire the pcm to the fuse box? or is that even what I am going to have to do?

 

When you say "I want to put this engine into my truck and still use the fuel injection ".... do you mean you want to use the LT1 engine's fuel injection (in which case you need the LT1 PCM and wiring harness to match the specific LT1 year engine). Or do you mean you want to somehow keep the TBI with the new LT1 engine?

The Holley Blue fuel pump isn't going to work with the LT1 fuel injection. That's a low pressure (9-14psi) pump for carb applications. You need a pump rated at least 200LPH, and capable or providing that flow at 43.5psi.

Note also that the LT1 heads have a D-port exhaust port, not the same as a Gen 1 SBC, so gaskets for headers might be an issue.

As noted, the LT1 PCM can be flashed to match the specific tranny configuration that you have. In any case the 94+ LT1 PCM's will have tranny control functions (both auto and manual versions) that will need to be edited out since those won't be required with your truck's manual tranny. The availability of a compatible VSS sensor for your tranny needs to be investigated. There are interface boxes available to match the sensor output to the LT1 PCM.

 

Yes, i want to use the fuel injection that caem with the LT1. I still have the factory wiring operating the speedo. Will I have to change this?

 

Does the stock wiring in the truck for the speed go directly from the vehicle speed sensor (VSS) to the speedometer? The LT1 PCM needs the VSS signal for some of its functions, like elevating idle speed when the vehicle is not at rest.

 

yes it does, is this something i need to convert?

 

I was in the same boat you're in now
I took a full size 92 Blazer tbi/auto and converted it to 95 dash with LT1/5 speed.

The easiest way to fix the speedo problem is to wire VSS into the input side LT1 computer and then wire the output side of computer directly to the gauge cluster. Skip the white box in the dash. You are not going to use it. The nice thing about this set up is that you can adjust your speedometer when you have the LT1 tuned. The pulse generator on the NV3500 is the same as the LT1 automatic

As far as exhaust, I just used my truck's long tubes with some thick copper gaskets

BTW, I spent about 2 days on the swap/fab work and about 2 months on the wiring

 

Thanks man. Two months on the wiring? Did you use a " stand alone" wiring kit for the swap?

 

I made my own wiring harness by tieing 3 different harnesses together. Thats why it took so long
That and I didn't know what I was doing at the time