I am wanting to start my first LSX project by converting my 65 Nova over to a 5.3 truck engine with an LS6 intake.

The local junkyards have several engines with reasonable mileage and good prices but none of them have the wire harness or ECM.

I am looking for advice on if I should wait until I find an engine with the harness and ECM? I have read that if you start changing the intake etc then it is better to just use an aftermarket wire harness??? What about the ECM? there are lots of ECMs on ebay that I could pick up.

Thanks for your input
Bret

 

It really depends on your budget. When I buy used pull outs the harness isnt that big of issue since I prefer to run a new aftermarket harness in most cases. The only way the stock harness would be worth anything is if you planned on turning it into a standalone harness yourself. If you have to pay someone for that you might as well just buy a new standalone harness. If you get the ecm for free or really cheap I would grab it. I sell them all day for $100 to give you an idea what they go for. Almost every place that sells harness's also sells ecm's so they are fairly easy to come by.

 

Definitely get the harness, ecu, pedal, tac, sensors, accessories as a package. You'll spend 2 - 3 times as much if you source individual parts.
Also, save yourself about $300 and skip the LS6 intake. While it supports more high end hp on the larger 5.7 LS1, you would really have to spin a smaller 5.3 and have a big cam to see a significant change over an LS1 intake.

 

Thanks for the input everyone. I would like to keep the budget under $2,000 for the swap.

Out of curiosity what companies make aftermarket harnesses? I don't have a problem with reworking a stock harness but would like to compare all options.

If I change from a truck intake to an LS1 intake would the same fuel injectors/electrical connectors work?

Cheers
Bret

 

will need different injectors, fuel rail and possibly injector connectors to run the LS1 intake

 

If you buy a flex fuel motor the injectors will fit the LS1 manifold directly. Other truck injectors need the plastic tip removed.
They are shorter so aftermarket rails can be used or use spacers that fit between the LS1 rail and injectors.

 

Are any of you using aftermarket wire harnesses or ECMs? If so where are you buying them?

 

Depending on what features and hp you want -do a search on the FI board on this forum for "Denmah or Microsquirt" both will give you alot of info on a stand alone management option.

Im running a Microsquirt on my LS engine and I love it. 6 months ago I had very little knowledge on EFI systems, now I can do my own harness and tuning. Very soon if not now you can buy a Microsquirt that is already modded for the LS engine so you dont have to do nothing but the wiring which is really easy.....

 

Check ebay, there are several there. Although there are variations within the various trucks as well as car wiring. There isn't just 1 generic harness. Check PSI conversions here too, they have some pretty good deals.

 

Also keep in mind that truck front accessories usually will have problem with using Car Intakes (LS1/LS6). You end up buying a car Front Accessories setup or modifying a Truckl one.

Added cost and effort... do you research before ... find out what will work and what will not so that you only have to buy once !...

BC

 

So I picked up a 2002 5.3 L this weekend. It had the wireharness w/ fuses and relays, ECM, the entire accessory drive, and starter with it.

Will the truck throttle body off my 5.3 work on the LS1 intake? Is their a difference between the ls1 intakes between different years?

When I have the ecm flashed, can a tune be done for a cam swap or do I have to do a dyno tune. I might have a good deal on an LS6 cam.

Cheers
Bret

 

The 3 bolt truck TB bolts right up to the LS1 intake.
Depending on which TB, you might have to remove the coolant crossover on the bottom. You will need to remove the idler bracket from the alt/ps bracket.
Water pump will depend on the TB.
A pic of my 05 5.3, truck DBW TB, LS1 intake, 5.3 injectors, aftermarket rails, cutoff idler bracket.

 

Sound like your pleased with the score you got on the 5.3L.. what did you end up forking for it ?

The tuner could but some basic fuel trim and timing changes in for what he know will safely work for the combination of what you have for internal (cam) and bolt on's...

But it is still best to get a dynoe tune or a Drivablity tune done.. else it is just a best guess if the tune will work out well or not.

BC

 

it was the best deal I could find within a 200 mile drive in the past month. I paid $800 for all of it. Has 89k miles. It has the 3 bolt cable driven throttle body on it.

I have LS1 Fuel rails and still searching for a good deal on a manifold. There are a few on ebay now. Also looking for a camero waterpump.

Is there a thread out there already that spells out what I am trying to do? I haven't found a good one yet..

 

http://www.ebay.com/itm/Camaro-Firebird-LS1-Intake-Manifold-w-Bolts-Used-OEM-12560688/290934687489?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D8616542167910558302%26pid%3D100033%26prg%3D1011%26rk%3D3%26sd%3D390275472498%26
This is the only one in good shape right now... thoughts?

 

Just an fyi, LS1 intakes on craigslist go for about $40 with rails here. I've bought 2 for less than that.
Definitely get the bolts, they cost me more than the intake (bought from GM dealer) on the first one I bought.

 

It seems everyone is way to proud of their stock intakes in my area and on Ebay!

 

The LS1 rail wont fit the truck injectors. The truck ones are too short. You can buy spacers on Ebay to get them to work, or you can use aftermarket rails.
On the water pump, the 98-02 f body LS1 pump wont work with the truck accessory spacing. You can use a later 07+ truck pump (with a little clearancing) or an 10+ Camaro pump.

 

I was going to pick up a set of camero injectors a guy was selling, but I am not sure what lb/hr rating I needed to get?

I know a lot of people have got the old ls1 water pumps and use an aftermarket spacer to make it fit the truck accessory system. Does the 10+ camero pump work without a spacer on the truck drive?

 

I have an LS1 intake...$40 plus shipping....PM me if your interested.