Lt1 Engine Harness & Swap
 

I am in the process of doing a swap on my 1970 c10. My question is what should I do with the wiring? Should I go with the painless kit or send it out to get it modified? Does anyone know where I send to get it modified? OO the motor is Lt1 is out of a 1994 Z28 and it is an automatic. And how would I remove all the smog pump stuff and the unnecessary sensors & components?

Re: Lt1 Engine Harness & Swap
 

Street and Performance in Mena Ark. I have been told Painless harnesses are not actually Painless.

Mike

Re: Lt1 Engine Harness & Swap
 

Thanks for the help.

Re: Lt1 Engine Harness & Swap
 

Im running into the same situation Ken. I have to swap an LT1 from a Caprice into my C10 and the painless harness seems nice but its too $$$ at $600 plus the reprogram. I may just end up reusing my stock harness with the addition of a VATS disable module. Keep us up to speed on your situation and progress.

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

I had my harness done by LT1 wiring. www.lt1350.com

Re: Lt1 Engine Harness & Swap
 

How much did they charge you?

Re: Lt1 Engine Harness & Swap
 

I used one from Howell Engineering on my 48.

Re: Lt1 Engine Harness & Swap
 

Man that must be a wild ride!:cool:

Re: Lt1 Engine Harness & Swap
 

I used a painless on my truck and had no problems. As far as the smog equipment, you just have to have it programmed out of the computer. Speartech or Street & Performance are two places that can reprogram the computer (around $200.)

Re: Lt1 Engine Harness & Swap
 

I believe is was around $300. They fixed two plugs on my harness and installed the V.A.T.S module. It is a true stand alone harness when I got it back. Its is about half the cost of a painless harness! Their current prices are listed on their website.

Re: Lt1 Engine Harness & Swap
 

Are you going to run AC?

Re: Lt1 Engine Harness & Swap
 

Yeah the vette motor in a fiero is definately a wild ride. almost scary how fast it gets up and goes. street and performance charged us like $1300 i think for the harness custom built to our lengths with all the connectors for every thing on there and the reprogramming of the computer. everything was soldered, heat shrinked. got an obdii plug. we could put the computer wherever we wanted and the plug wherever we wanted. pricey, but nice

Re: Lt1 Engine Harness & Swap
 

I have the AC pump and stuff, But im not going to run it. I still have the complete z28.

Re: Lt1 Engine Harness & Swap
 

Update: Got my harness from spear tech. Cost me 800 Bought a new harness and sent in to get my computer reprogram.

Re: Lt1 Engine Harness & Swap
 

Smog-wise you don't have a lot to worry about in the PCM aside from programming out the EGR valve if you want that gone.

The pollution pump is electronic, and I don't believe that system is in the computer at all. Just unbolt the pump, leave the connectors hang, and plug up the exhaust manifolds/headers.

After that the only thing you'd have to worry about is the O2 feed after the cat(s.) But since your car's a '94, you don't even have one.

The rest of the sensors are needed to run the engine properly.

Re: Lt1 Engine Harness & Swap
 

I go to church with a guy that put a 3.8 in a ferrio.......they say it skates the front end if they shift gears hardenough:crazy:

Re: Lt1 Engine Harness & Swap
 

Ive got a question about these harnesses. Do they just cover the motor or the whole truck? I mean am i going to have to buy or fashion wiring to run to the lights, A/C, gauges, etc.? The LT1 Painless harness doesnt mention anything about it but my buddy HartRod said his 67-72 Painless harness covers the whole deal.

low4life1 - I cant make heads or tails of the S&P website...can you tell me what exactly you ordered?

pdr510 - I will be running A/C. Ive been told I need to notch the frame or get a vette setup...any ideas?

Thanks

Re: Lt1 Engine Harness & Swap
 

Send it to Speartech, it's cheaper than S&P and the work is of the same or better quality. Google for them if you need to. They're on the LS1tech forum. This is an idea of their LS1 harness and the things you can expect from them:

http://www.ls1tech.com/forums/showthread.php?t=583994

Look at post #7.

Re: Lt1 Engine Harness & Swap
 

I think Painless normally covers the whole truck and includes the new fuseblock if you get that package. With Speartech, it covers the harness for the engine, gauges and peripherals along with relays and fuse blocks to protect your wiring from what I gather. If you go for a less expensive solution like Wait4Me Performance, like I did, it covers just modifying the harness and you gotta install the relays and fuse blocks/fusible links yourself.

Here's the thing - you can re-use a lot of your factory wiring. When I just redid my wiring, i have a 1-wire alternatore on the new drivetrain, so i deleted the voltage regulator, tied together the three hot wires that were on there (one for voltmeter gauge, one for interior dash power), then taped it up. headlights will still be running the same power run as before, gauges will still use that power lead. Then you can use the part of your harness that previously did starter, HEI and other gauges accordingly (delete the unnecessary gauge wires, use IGN purple wire to the starter on new engine, and HEI wire for fans or something similar).

Re: Lt1 Engine Harness & Swap
 

I would do that but im not starting with a whole truck. I bought the cab, frame, bed and front clip all seperate so im either buying a body harness/block AND an engine harness OR im fabbing everything myself. I think the normal 18 circuit Painless harness is about $400 and I think I can get an engine harness for $200 so thats still cheaper than the LT1 Painless or S&P harness. Suggestions?

Re: Lt1 Engine Harness & Swap
 

Suggestions?

Unless that harness is pre-modified, just go all Painless or call Speartech for the closest thing to a plug-and-play install. Here's the deal:

If you get a harness for $200 and it has to be hacked, that is $200-400 worth of work if someone else does it. That's $400-600 total. For $750 you can get the pimp-daddy Speartech harness that kicks ass.

Best thing to do? Call Speartech. Call Painless. Talk to a tech about your situation. You are going to learn more from that phone call than you will with 10 days worth of posting messages on an internet forum.

Be sure to share your findings :)

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

LT-1's like Hooker long tubes from what I've heard from a bunch of guys with way more experience than I.

Re: Lt1 Engine Harness & Swap
 

I am running the bower's ac relocate bracket. www.bowersrodshop.com is the website you can get the info. I have seen the whole corvette set up on ebay from time to time. I have seen pictures of frames notched to make the ac clear. It was not something I wanted to do.

Re: Lt1 Engine Harness & Swap
 

Harness came in today.
http://img292.imageshack.us/img292/4777/dsc03341dc4.jpg

Re: Lt1 Engine Harness & Swap
 

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

http://img136.imageshack.us/img136/3271/1wk8.jpg

http://img136.imageshack.us/img136/8484/2zs2.jpg

http://img144.imageshack.us/img144/782/3iw3.jpg

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

PS - here is a link to more help:

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

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & 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

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

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.:alc:

Re: Lt1 Engine Harness & Swap
 

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.

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

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

Re: Lt1 Engine Harness & Swap
 

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.

Re: Lt1 Engine Harness & Swap
 

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?