LS & Vortec Swap to 90-91 VSS Electronic Gauge Cluster

[RoryH19]

Here's an article I found (there are many) for a blazer swap.
It mentions fuel lines among other parts of the build.
Looks like they added fittings to their sending unit along with a high pressure pump.
Some other useful info too for those that want to keep the 700R4.

http://www.trucktrend.com/how-to/engine/1111tr-6l-engine-swap-1982-chevy-k5-blazer/

I'd like to keep as many OEM parts too, helps with future servicing and repairs.

 

[RoryH19]

You can eliminate the range switch on the side of the 4l60e if you like. I had a brand new one sitting there to install but decided to bypass. Fewer components to troubleshoot.

Good to know. I may try that if I run into problems.
Do you have the details on the bypass?
Also your k10 has the same setup as my k5 except for the engine.
Not sure why a 308 was put in the rear diff from GM.

 

[rpcraft]

There is also some youtube video on the wiring for the 91 Burb gauges from Lonnie Rice. It is not K5 specific but the only thing really on a K5 that you need to adapt is the 4wd light...

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- Part 1

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- Part 2



Following that up William Green did a good job on his K5

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If you need VSS from a NP208 Dokota has an 8K signal adapter that converts mechanical to digital and you can use it to feed the PCM, and then the gauge. You just have to have your tuner set the PCM for the 8k signal or your trans will not shift right and I have found that no matter how many times you tell them they forget it so what I would plan is a base tune for your pcm and harness, then haul it to a dyno and have them tweak the 8k signal and then proceed with a proper dyno tune.

Sorry if I am jumping in at the end and someone repeated any of this. I was not in the mood to read too much today, lol.


Here is the DD 8k unit for about 30 USD - https://www.ebay.com/itm/Dakota-Dig...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

 

[rpcraft]

I have a list of Dorman parts you can use on a K5 fuel system for the LS swap. It is not available right because it is on my Home PC. I can revisit over the weekend and update it. Total cost was about 100 bucks overall and it is the nylon tube, brass fittings for splicing the tubing, and then the adpaters for the fuel rail and compression fittings for the fuel filter and stuff on the gas tank.

 

[rpcraft]

Good to know. I may try that if I run into problems.
Do you have the details on the bypass?
Also your k10 has the same setup as my k5 except for the engine.
Not sure why a 308 was put in the rear diff from GM.

Yes and that range switch really is just the nuetral and reverse switches, which is already built into your steering column and factory ignition harness.

 

[rpcraft]

Good to know. I may try that if I run into problems.
Do you have the details on the bypass?
Also your k10 has the same setup as my k5 except for the engine.
Not sure why a 308 was put in the rear diff from GM.

3.08's are probably the most common gear set in the k5's across most all years FWIW.

 

[rpcraft]

I have a list of Dorman parts you can use on a K5 fuel system for the LS swap. It is not available right because it is on my Home PC. I can revisit over the weekend and update it. Total cost was about 100 bucks overall and it is the nylon tube, brass fittings for splicing the tubing, and then the adpaters for the fuel rail and compression fittings for the fuel filter and stuff on the gas tank.

Best Fuel tank to use is a TBI blazer tank with the matching sending unit and then use a fuel pump from any 1996 up GM gas powered truck.

 

[Camar068]

Good to know. I may try that if I run into problems.
Do you have the details on the bypass?

Look at pin 34 on the blue connector....see note highlighted in green. It says the same for 99-02 and 03-07 harness's. This wire will hook up to the current vehicles neutral safety switch wire.


http://lt1swap.com/2004vortec_pcm.htm

 

[RoryH19]

Thanks @rpcraft and @Camar068 for the info. I'll look into reusing my np208 first with the DD to shift the trans. This would allow me to use my current gauge cluster and the 4wd shift light would stay the same. I can change to a 90/91 np241 and gauge cluster if needed later.
For the fuel tank, I was thinking a TBI unit as well since it's already setup for fuel injection. There is probably some baffling to keep constant fuel to the pump.

 

[rpcraft]

You are correct, the TBI tank has a small baffled portion at the bottom of the tank that acts as an anti-slosh mechanism for an in tank pump and the purpose is to help keep the pump in fuel so that it cools and lubricates the pump, as well as prevents air breaks in the fuel rails.

 

[RoryH19]

One other thought.

Since I'm me and need every factory option to work...have any of you setup cruise control on your LS swap?
I found these writeups:
https://ls1tech.com/forums/conversi...t-gm-cruise-control-your-cable-driven-tb.html

http://67-72chevytrucks.com/vboard/showthread.php?t=511477 This one has DBC and DBW info

While on the subject is it better to have DBC or DBW? Does having 4WD change the recommendation?

 

[yevgenievich]

Dbw simplifies cruise control, but requires pedal swap. Dbc simplifies pedal set up, but requires cruise module wired up

One other thought.

Since I'm me and need every factory option to work...have any of you setup cruise control on your LS swap?
I found these writeups:
https://ls1tech.com/forums/conversi...t-gm-cruise-control-your-cable-driven-tb.html

http://67-72chevytrucks.com/vboard/showthread.php?t=511477 This one has DBC and DBW info

While on the subject is it better to have DBC or DBW? Does having 4WD change the recommendation?

 

[rpcraft]

I have not done it yet but my LS setup is the drive by cable so in my setup I already have the pigtail and the servo control out of the mid 90's 1500 trucks. It's pretty much a bolt on for that. I'm still doing the wiring on my riig and fixing some patch panels but the links in the files section of the LS swap squarebody trucks on facebook has a wiring diagram for setting it up using the factory stalk on the square bodies.

 

[RoryH19]

I think I'll go with the DBW setup. I can live with the different pedal.
I've read that some use a diesel gm truck pedal which looks closer to stock.
I just have to get the TAC module from the donor too.
Going to look at a 6.0/4l65e setup from a 2004 Denali AWD later today.
This should allow me to connect my 208 t-case or a 241 if I want the electric speedo.
For now I can just use the DD to shift the trans.

@rpcraft have you been able to gather the info on the fuel plumbing?

 

[rpcraft]

Sorry for the delay if there was one. for some reason the drawing was missing from my pictures folder. Luckily I had a backup on google.... I've just linked it directy from there but you should be able to download and save it if you need to.

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This setup uses brass compression fittings on the sending unit instead of any AN adapters. They should work fine. My LS setup is a truck style intake with a regulator on the rail so it includes a return line back to the tank. I think the distance is around 17 feet for both lines so if you are doing this on a truck you will probably not need the one 800-012 coupler on the return line but then again if you decide to run a blazer tank like some fellows do you might end up needing it. I do not recal the exact price but I seem to think with the filter, tank, sending unit, and pump it was all around 250 USD and on the clips I used a set of bull nose wire cutters to clamp them on and I can gaurantee you they won't be going anywere, but for some reason I just liked the idea of having two clips per connection.


Photo for reference on the tank sending unit... The line I still have open is going to get some low pressure fuel hose run to it with a one way Tank vent that comes off the Third Gen camaros but technically there is a vent tube in the filler neck so I could cap it off and leave it at that if I wanted to (I think). Since I am not 100 % sure on that I'm still going to vent it. Not sure on the part # yet but I just saw one on the Camaro forums the other day (Because I knew they had one). I'm probably going to run it up into one of the tail light housings so it's not prone to water flooding (in case I go swimming in the JImmy).

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