Author Topic: LS376/515 swap in a '78 Trans Am  (Read 1053 times)

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #40 on: January 22, 2019, 08:09:58 AM »
Pictures!  Although, I don't think they capture the amount of work done...












Nexus

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Re: LS376/515 swap in a '78 Trans Am
« Reply #41 on: January 22, 2019, 10:55:11 AM »
Progress is the difference between visual progress where it looks like lots gets done with little work and actual progress where the hours put in go unseen as all you did was put in new wiring...how hard can it be?

lol...get work and keep ticking away at it...I look forward to more updates!!!
Charlie

79 Esprit but like many, it will be a T/A clone
(18 years and counting but still have her)

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #42 on: January 22, 2019, 02:38:41 PM »
I have been studying the wiring a lot ...  The Holley system has provisions to get engine temp and oil pressure so it can do it's job, what I haven't been able to find is how to get oil pressure and engine temp to the Dakota Digital VHX new gages.  I called both Holley and DD today to ask how they have done this in the past and was disappointed to hear each of them respectively pointing fingers at the other.  Both suggested that I use two sensors for each- one each for Holley and DD.  Surely that can not be a very good solution?  DD has an interface box, another $100, that is specific to the Holley EFI systems but, "they can't guarantee  that Oil pressue will go accross".

So, where are there other ports for engine temp and Oil pressure?  Isn't there Oil Pressure by the oil filter- I maybe just drill and tap for 1/4" NPT?  Also, any suggestions on pressure sending units for LS?  The Holley unit they told me to get is another $135!!!!  Who buys a $135 oil pressure sending unit?

FormTA

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Re: LS376/515 swap in a '78 Trans Am
« Reply #43 on: January 22, 2019, 02:56:14 PM »
I drilled the boss by the oil filter. I don't know what the LS3 has, you may need to get an ls1 version. I'll see if I can find a picture. I drilled the top of my water pump for my temp sending unit.
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

Updated71

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Re: LS376/515 swap in a '78 Trans Am
« Reply #44 on: January 23, 2019, 09:58:16 AM »
I initially did the boss by the filter too, but didn't like how close it put the large sender so close to the header tubing.  It definitely got quite hot.  I eventually moved it to the factory location on the valley cover using a T fitting I found on line.  One end is for the gauges and the other is for the PCM harness. 

This is the on line pic I used for reference.  I can take a pic of it on my car and get the fitting info if this is a direction you'd want to go. 

The surgeon general never said nuthin' 'bout smokin' the competition!

Re: LS376/515 swap in a '78 Trans Am
« Reply #44 on: January 23, 2019, 09:58:16 AM »

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #45 on: January 23, 2019, 03:32:56 PM »
I initially did the boss by the filter too, but didn't like how close it put the large sender so close to the header tubing.  It definitely got quite hot.  I eventually moved it to the factory location on the valley cover using a T fitting I found on line.  One end is for the gauges and the other is for the PCM harness. 

This is the on line pic I used for reference.  I can take a pic of it on my car and get the fitting info if this is a direction you'd want to go. 



I would appreciate that- I too am not wild about having sensors that low and right next to headers.

Thanks.

Updated71

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Re: LS376/515 swap in a '78 Trans Am
« Reply #46 on: January 23, 2019, 03:50:34 PM »
I did buy it from over seas.  It came very quickly though.    Approximately 3 weeks if I remember correctly.  Google the part number and maybe they are now available here.  Either way, I am pleased with the way this went. 


https://www.aeroflowperformance.com/af166-05-02s

The surgeon general never said nuthin' 'bout smokin' the competition!

Updated71

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Re: LS376/515 swap in a '78 Trans Am
« Reply #47 on: January 23, 2019, 03:56:30 PM »
Also, I believe I needed a slightly longer coupling for the factory sensor up top.  That was about $2 in the plumbing department locally.  The sensor is what is required for my Speedhut gauges.  It is a common early GM sensor.


The other part of your question was engine temp.  My Speartech harness gets temp info from the drivers side front of the head near the first plug wire.  I added the Speedhut sensor for my gauge to the same spot on the passenger side, but at the rear of the head (the heads are the same so looking at it from the passenger side puts that port opposite of the drivers side).  I had to remove a factory pipe plug and use a metric to standard adapter IIRC. 

I couldn't find a way to just use one sensor in either application.  They both use a different input signal to read correctly.
« Last Edit: January 24, 2019, 08:43:59 AM by Updated71 »
The surgeon general never said nuthin' 'bout smokin' the competition!

ryeguy2006a

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Re: LS376/515 swap in a '78 Trans Am
« Reply #48 on: January 24, 2019, 02:29:37 PM »
So, I understand why DD needs the oil pressure sender because that is what you will see on your cluster, but I'm curious why the terminator needs to see oil pressure? I don't believe that my dad's Terminator kit had an oil pressure sender in his kit? He had a fuel pressure sender in the kit. Is there an option with Terminator to kill the fuel pump if it doesn't see oil pressure or something?

On both of my LS swaps, I deleted the factory oil pressure sending units because they don't tie into the ECU. I have thought about wiring in a fuel pump kill switch inline with the fuel pump relay to kill the pump if the oil pressure dropped below like 5 psi.

1976 Trans Am LS1, 6 speed, C5 12.8" Brakes, LS1 rear 12" brakes, 17" Aluminum Rims, and much more...SOLD
My Build: http://transamcountry.com/community/index.php?topic=24465.0

New project: 1968 Camaro with 6?.?0?  5.3 w/ Z06 cam/T56
http://transamcountry.com/community/index.php?topic=74591.0

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #49 on: January 25, 2019, 07:50:23 AM »
A little break from wires..







jonathonar89

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Re: LS376/515 swap in a '78 Trans Am
« Reply #50 on: February 04, 2019, 09:51:12 AM »
Do you have any more pics of the Dakota Digital install?

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #51 on: February 04, 2019, 09:53:30 AM »
Do you have any more pics of the Dakota Digital install?

Not yet, soon though.  Are you looking for anything in particular?

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #52 on: February 04, 2019, 09:57:57 AM »
Moving back to the engine bay...  Spent entirely too much time, and time I don't think I had in order to be running for the March 9 Lone Star Good Guy's Autocross, on the inner fenders cleaning out the undercoating and filling holes.  With the new layout, there won't be any wires showing and the inner fenders are going to be clean- so I had to make them presentable....  That turned in to the rest of the engine bay and that consumed the entire weekend.  I have to say I am pleased with the result!







jonathonar89

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Re: LS376/515 swap in a '78 Trans Am
« Reply #53 on: February 04, 2019, 10:02:29 AM »
Do you have any more pics of the Dakota Digital install?

Not yet, soon though.  Are you looking for anything in particular?

Just curious to see how it mounts behind the dash bezel.

FormTA

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Re: LS376/515 swap in a '78 Trans Am
« Reply #54 on: February 04, 2019, 02:50:16 PM »
Were your gauge made from stock images or did you upload your own image. I like them, they look close to stock.
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

Re: LS376/515 swap in a '78 Trans Am
« Reply #54 on: February 04, 2019, 02:50:16 PM »



jonathonar89

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Re: LS376/515 swap in a '78 Trans Am
« Reply #55 on: February 04, 2019, 04:26:21 PM »
Were your gauge made from stock images or did you upload your own image. I like them, they look close to stock.

That’s the gauge setup from Dakota Digital.  Only comes that way.

FormTA

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Re: LS376/515 swap in a '78 Trans Am
« Reply #56 on: February 05, 2019, 07:09:59 AM »
Oh, for some reason I thought he said he was using speedhut sending units so I figured the gauges were speedhut too. They look nice. Thanks!
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

skisix38off

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Re: LS376/515 swap in a '78 Trans Am
« Reply #57 on: February 05, 2019, 07:18:28 AM »
Were your gauge made from stock images or did you upload your own image. I like them, they look close to stock.

These are Dakota Digital's VHX gages for a Pontiac.  They are close to the factory looking gages, not a re-done factory gage though.  I got new gages because:
1) I had to do something to get a speed reading.  The T56 only outputs a VSS signal, so I either had to buy a $300 adapter to go to the factory gage or buy a new digital gage to read the VSS signal.
2) With the new engine I wanted a more trustworthy reading of oil and water temp.
3) I wanted to be able to read the gages at dusk, not just full dark.

Re: LS376/515 swap in a '78 Trans Am
« Reply #57 on: February 05, 2019, 07:18:28 AM »
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