LS ECU is best mounted where ?

[Chevylife]

One of the best parts of our 60's and 70's trucks is they are simple yet versitle.
This year my 67 C10 will be 57 years old. I still really like the truck. Five lug conversion, disc brakes, internal regulator alternator, headlight relays, HEI distributor, Power electrical wiring upgrade. Fun, simple upgrades/updates.

This year since GM has worked out the kinks on their LS motor thing (27 years).
I am going to try one. The hardware I think I have worked out. Electronics, a stand alone wire up. ECU placement talks to me saying under the dash. Drivers side and use the clutch rod hole to the new funny looking motor. I see posts that it has been used. Long term thoughts on using it I can't find.

To the pioneers of LS conversion on the Forum
Thoughts on using it ?
Why did you choose your location?
Are you happy with it ?
Wish I would have done it this way ?

Sure not happy cutting bed wood for a gas tank fill hole but I did one of Patrick's ( Pjmoreland ) dummy filler neck kits. Works and looks great. Great work Patrick ! The truck and me are smiling again.

[LS short box]

I've done a number of LS swaps over the years.
Wiring harness/ecm for the engine and trans. I've used Speartech and Howell. Both have provided great products and great tech support. I would never buy the cheap ebay harness/ecm's.
If your 67 still has the as delivered chassis wiring harness I would replace it. LS swap need really good grounds and 12 positive wiring.
On my LS swaps I try to hide as much wiring as possible.
On my 68 C10 LS6 swap I mounted the ECM and fuse block behind the glove box. I had to section the glove box a bit to make room. OB2 port on the heater box.
Some use truck FEA. I like 2002 Camaro FEA with an LS6 intake. Speed Engineering headers. I know they are made in China but they fit well and I can't afford $1200 for just headers.
Couple of pics.

[54blackhornet]

Magnificent looking engine bay I must say ! Congratulations !

[cj847]

This is one of my pet peeves. Why do people stess the location of the PCM? It is under the hood in the vehicle you got it from. Why waste precious interior space on it?

Anyway, on my 67 the PCM and associated fuses/relays are located in the driver front fender area (near the horn). Basically the same spot it is in a Silverado pickup.

PS> I have put a PCM in the interior of another vehicle and hate it. It has a huge wad of 100+ wires running thru the firewall to the PCM. On my 67 I have about 10 wires going thru the firewall related to the LS.

Keep it simple!!

[LS short box]

Thanks for the kind words engine bay wise.
As with any project to each his own on the build.
My current 80 Camaro project LS3 swap and a 73 Camaro LS3 project I did a number of years ago. Tried to hide as many wires as possible. LS engine/trans harness and stock Camaro chassis wiring harness.
ECM and TCM are attached to the heater housing on the inside of the car.
On the 68 pic you can just see the grommet for the wiring harness slightly above the back of the right coil cover. I would of gone lower but I needed to clear the heater housing on the inside. Unless there is a major problem all trouble shooting is done thru OB2 port.
Couple pics of the orange 73 and blue 80 engine compartments.

[Hatzman]

I mounted mine behind the passenger side bench seat. I created my own mount and routed the wiring harness along the transmission and through the floorboard.

Completely hidden and out of the way.

[Richard]

IMO, it needs to be in cab or if under hood in an enclosure. My ECM will be under dash with harness through clutch hole. If vehicle is for show only or never driven in the rain, put it anywhere you want to. Never have seen an ecu exposed to the elements under hood in any OEM vehicle. Manufactures will not spend a penny on anything that is not necessary. To each their own if you just put it under hood with no protection.

[A1971Blazer]

Many factory vehicles have the ECU mounted under the hood.
There is limited room under the dash especially if you are adding AC, either factory or aftermarket.
I chose to mount mine to the back side of the core support along with a custom load center for the wiring harness.
I also made a custom cover for the bulkhead connector to hide the forward harness.
It's not a daily driver and won't be in the rain unless of course I get caught in a rain shower while I'm out in it.
2002 LS1 from a TransAm WS6
I used a factory GM mounting bracket and I have a cloned PCM just in case...
I can easily remove and replace it in 15 minutes.

[MARKDTN]

For any kind of driver I would leave it underhood. All LS (and LT1 and Vortec) PCMs are weatherproof and were mounted under the hood from the factory. No so with all TBI and TPI although for Speed-Density TPI they were underhood on Corvettes and the same PCM was used on 3.1 Cutlass, Lumina, Grand Prix..... I do like fuses inside if possible. But behind the glove box-especially with A/C-is taking up valuable space.

[Willie Makeit]

mounted all of mine on the backside of the radiator support, down low between the support and the inner fender. have mounted them on the driver side as well as the passenger side. shorten a few wires. lengthen a few others. i like to hide my wiring as well and it allows the wiring to run low and out of sight. if i didn't point the ECM out, 99% of the folks looking at the engine bay would never see it.

[LS short box]

So as I said above I like to hide wires but on my 98 Wrangler with a 2002 LS6/4L60E swap the ECM has had been in the engine compartment for over 15 years. Zero issues. Rain and or snow and its been bullet proof. Knock on wood but I haven't had a GM ECM fail in my daily drivers or in my hot rod projects.
In the pic you can see the ECM just below the brake booster.

[bigmoe]

My 65 LS swap was my first. My goals were to keep costs down and to keep changes from original to a minimum. In my mind the more changes the more chances for complications. I had the wiring harness from the donor vehicle so I sent it off to have it thinned and put the fuse/relay set up on the terminal end. A lot cheaper than buying a custom harness and guaranteed to have all the right connectors. etc. and fit the engine just how it was in the donor. Unfortunately this meant the harness had to lay out as it had on the donor with the harness exiting toward the driver fender. I mounted the ECU as far forward as I could. My Air filter sits just above so that it partially hides it.

[Accelo]

I used this location on the firewall.
I understand this only works if the heater/air-conditioner has been relocated. I used a modified original harness and was severely limited by the length of the stock harness.

[Rickysnickers]

Flipped