Lt1 Engine Harness & Swap

[Kenneth_CS87]

Harness came in today.

[Kenneth_CS87]

Do you guys know if this is needed? And what is it?

[Rat72]

I've done a few of the LT1 conversions and the best and cleanest results always started with the stock harness. The last one I did was with a Painless harness and it was bad. The wire length was a mess and there was a bunch of wires missing.

As for the PCM, you can program it yourself with LT1Edit. Even with little programming skills you can eliminate the VATs, change the idle, modify it for larger injectors and more. If you go crazy you can program it to do anything you want. If you don't want to hassle there was a company called PCM4less that was very reasonable.

Good Luck,
Whit

[Hart_Rod]

Kenneth - I believe the sensor in the first picture controls the EGR, most people remove it. I'm not sure about the other two.

Rat72 - Where do you get LT1Edit at? How much?

I used a Howell Engineering harness in my 48 and had no problems.

Here are a couple of links that might help:

http://www.fierolt1.com/top-end.htm

http://www.fierolt1.com/bottom-end.htm

http://www.theherd.com/articles/lt1_cool.htm

[shifty]

PS - here is a link to more help:

http://67-72chevytrucks.com/vboard/s...ad.php?t=52057

[Kenneth_CS87]

Originally Posted by shifty

PS - here is a link to more help:

http://67-72chevytrucks.com/vboard/s...ad.php?t=52057

Thanks All I need is know now is:
A/C Delet
EGR Block off
Throttle Cabel Setup
Headers
Radiator
External fuel pump.

[Slammed70]

Originally Posted by Kenneth_CS87

Does any know what good header setup would work with the swap?

A good set of 1 3/4 headers will wake up an LT1.....just becareful where as they are a "D" port and a straight plug design. I assume since your putting one of GMs mistakes into your truck you are going for performance....so Im sure I wont need to tell you to run long tubes. Only problem with headers are the O2 sensors, you will have to make some extensions for them. SLP sells them for $65 a pair if I remember right. Or you can make your own, but if you do make your own...SOLDER them, DO NOT crimp the wires together with butt splices. O2s operate on 200-500mv so and little bit of resistance will **** you all kinds of up.

As far as the smog goes....its 94 and OBD1 so you can just unhook/cap everything off. You need to remove the balencer in order to take of the tube that connects the A.I.R. Atleast I did in the car....if the motors out Im sure you will have enough room to fanagle it out. The smog pump on that cars electric....help in by three bolts, unhook it and throw it in the trash, but that will leave a 3/4 port on your air intake duct open. As far as the EGR goes....chuck it, theres two ports on the back of your intake you need to block off, or spend $300 and buy an LT4 intake. The LT4 intake doesnt have any emissions anything on it....just one vacuum port on the drivers side for the booster, and the PCV valve/vacuum port thingy. You will notice the car runs 10 degrees cooler and has more power....but runs a bit richer.

And those vacuum/electrical things you posted pics of, you dont need them. If you follow the hoses...they all lead to a T on the rear of the intake....which lead to the EGR valve and the EGR solenoid. So you can chuck them along with your EGR system. And the connectors are all them "weather pack" style so nothing bad will come from leaving them to dangle. And that thing on the front by the throttle body....I dont know what that is, neither my 95 nor my buddies dads 92(vette) has it.

Just a suggestion...hit up Dynaspark and get rid of that ****ty gen I opti-
http://www.dynaspark.net/products/


Hope that helped, if you need anymore info or advice on LT1 go-fast parts just let me know, Ive owned two F-Bodies and built 15 or so of them engines.

Mitch

[Kenneth_CS87]

I think ima go With this fuel pump. http://store.summitracing.com/partde...5&autoview=sku

[brak]

you might want to do some research on the emissions requirements...

It's been 3 years since i left the CHP to go active duy military, so it might have changed, but as it was, Installing a newer "emissions controlled" motor into your classic vehicle, negates any exemption you may have. the motor was designed to have emissions equipment, and therefore must be tested.

do your research now, and save yourself a headache later

[BowTieOgre]

Originally Posted by Slammed70

Hope that helped, if you need anymore info or advice on LT1 go-fast parts just let me know, Ive owned two F-Bodies and built 15 or so of them engines.

Mitch

I certainly helped ME. I am doing the same swap and really appreciate guys like you who have the knowledge we need replying with LOTS of info. Happy 21st btw.

[shifty]

Originally Posted by Slammed70

theres two ports on the back of your intake you need to block off, or spend $300 and buy an LT4 intake. The LT4 intake doesnt have any emissions anything on it....

I thought you had to have LT4 heads in order to use the LT4 intake? The angle of the heads to the top of the block is diff't.

In some year ('96 or '97), all Corvette engines were LT4, right? I suppose it would work then, but ... I am sketchy on that one, I just recall reading that the block of the LT1 and LT4 are essentially the same, but the heads have diff't angle.

[pdr510]

Originally Posted by Kenneth_CS87

I think ima go With this fuel pump. http://store.summitracing.com/partde...5&autoview=sku

I am using the same pump. Works good. Here is a helpfull website with some info on the LT1's: http://shbox.com/1/4th_gen_tech1.html

[Kenneth_CS87]

Originally Posted by pdr510

I am using the same pump. Works good. Here is a helpfull website with some info on the LT1's: http://shbox.com/1/4th_gen_tech1.html

Are you using the stock fuel tank? What did you go with for headers? I went with the hooker super comp.

[pdr510]

Originally Posted by Kenneth_CS87

Are you using the stock fuel tank? What did you go with for headers? I went with the hooker super comp.

I am using a blazer tank. I used the stock tank with the '72 sending unit for a few months before I installed the blazer tank. I used the hooker super comp headers. Welded o2 bungs in the collectors.

[Kenneth_CS87]

Originally Posted by pdr510

I am using a blazer tank. I used the stock tank with the '72 sending unit for a few months before I installed the blazer tank. I used the hooker super comp headers. Welded o2 bungs in the collectors.

How did u use it with the stock tank? I dont think I have a return line on my tank. Any pics of the tank setup u have now?

[BarryB]

Originally Posted by low4life1

I just did a zo6 vette motor in a fiero and we used a street and performance harness. Very nice. custom made it for us to the measurements we gave them. Big money, but very nice and went in with no problems. I think the painless ones need a little more work that the street and performance one did

God oh mighty!! You have to post pics of that thing.

[pdr510]

Originally Posted by Kenneth_CS87

How did u use it with the stock tank? I dont think I have a return line on my tank. Any pics of the tank setup u have now?

I don't have any pics of my setup. I can get you some and post them tomorrow if you would like. As far as the stock tank I used the vent line on a '72 sending unit for a return. The blazer tank I used the vent port on the passenger side for a return. I recommend moving away from the stock tank. I could hear the gas flowing inside the tank. It functioned ok though.

[Kenneth_CS87]

Im in the Process of Installing my harness. Does anyone know which wire is the Parking/Neutral signal wire?

[Slammed70]

Originally Posted by shifty

I thought you had to have LT4 heads in order to use the LT4 intake? The angle of the heads to the top of the block is diff't.

In some year ('96 or '97), all Corvette engines were LT4, right? I suppose it would work then, but ... I am sketchy on that one, I just recall reading that the block of the LT1 and LT4 are essentially the same, but the heads have diff't angle.

I did do the LT4 conversion....but no you dont have to get LT4 heads. The only difference is the intake runners are taller and flow WAY better then then the stockers. The LTX blocks are all the same....LT1, LT4, even the 265 versions used on the Caprices/Cadillacs are all same.

LT4s onlt came in the 96 Gran Sport Vettes with 6 speeds. And a very select few of the Firebird Firehawks and Camaro SSs had them....like 15 of them that SLP got their hands on.

Also....if you want further proof on the interchangeabilty on the two parts, the LT1 and LT4 use the same intake gaskets.

[shifty]

Intake gaskets would only account for the port, not the angle of the head to the top of the block though.

You're 100% sure that the angle of and LT4 head and an LT1 head is exactly the same? See post #8 in this thread. We just had a discussion about this @ LS1tech:

http://www.ls1tech.com/forums/showthread.php?t=604047

I am curious if all the people I've talked to are misinformed, or if maybe you're mistaken.

[Slammed70]

Originally Posted by shifty

Intake gaskets would only account for the port, not the angle of the head to the top of the block though.

You're 100% sure that the angle of and LT4 head and an LT1 head is exactly the same? See post #8 in this thread. We just had a discussion about this @ LS1tech:

http://www.ls1tech.com/forums/showthread.php?t=604047

I am curious if all the people I've talked to are misinformed, or if maybe you're mistaken.

Since I dont have the time...or patience to rip my LT4 intake off and mock it up on a set of heads and take some pics for you. Ill just refer you to this site.

http://www.grandsportregistry.com/lt1vslt4.htm#GASKET

Also, I dont want to argue about this with you....where as Im relativly new here and dont want to make anybody amgry with me.

[shifty]

I'm not trying to argue, I'm genuinely asking. I have always heard this, so I was hoping you could give me some insight. I really appreciate the link. I admittedly don't know a gaggle of info about the LT-based engines, so I was asking to gain knowledge, not to challenge you (don't be so quick to judge )

[shifty]

By the way - I promised someone around here I was going to report back to them on this stuff...about problems with LT1 and what you should be aware of before you finish your swap.

Well, here is the link: http://67-72chevytrucks.com/vboard/s...6&postcount=46

[70rs/ss]

Good stuff, I seal all my intakes with Ultra copper on the ends!! I got a response from speartech on the 6.0 and the LT1, $450 apiece to make my factory harnesses nice and pretty and to be plug and play, and $300 to do the ecm for the 6.0 and $150 for the LT1. They said they'd drop $100 off if I did both, so I'll do them together to save $100. Thanks for the advice and direction shifty!! I was a little in the dark and going several different directions with all this stuff!!

[shifty]

Let me know how your experience with Speartech is. Those guys seem to be great, they are very responsive in answering all kinds of questions over at the LS1tech.com forums, even if it ain't gonna net them any business (i.e. if you ask a question about harnesses, those guys will actually answer it, amazingly enough)

Glad to hear you're getting going on it. Amazing that you can spend almost as much on the computer, programming and harness as you do the engine