Hack a factory computer, or MS?

I'm currently searching for an LQ9 for my El Camino. (that means a 6.0L LS-type high output chevy truck engine). Plans are pretty simple. It already has 10:1 compression and really good cathedral port heads, so I think I'm just going to replace the wide-LSA cam with something in the 224/234 duration range and a tighter LSA to get me up near the 400+ mark.

The problem is, I can find tons of LQ9 engines for around $1000 from LKQ or junkyard, but they are engine-only. I want engine, harness, and ECM. Until I buy the additional harness and ECM it sorta kills the deal. Should I pony up for the harness and squirt it, or will I have a better time tuning with a factory ECM? Emissions is not an issue here in PA, its visual only in an 86 elky.

Use the factory PCM.

factory no doubt. gm pcm's are so infinitely controllable and tunable via laptop. i have hptuners and with never having tuned EFI beyond an old holley 4D system that had dials on the computer to tune fuel mixture, i got it running better than it was on someone else's tune.

search a complete dropout with the harness and pcm, they're on there and the junkyards that sell them seem to put their better guys on them. when i've bought them they have been very carefully removed and packaged.

patgizz wrote: search a complete dropout with the harness and pcm, they're on there and the junkyards that sell them seem to put their better guys on them. when i've bought them they have been very carefully removed and packaged.

Yeah, but the ones I've found are $2500. I can buy an engine for $1000, why should I pay $2500 for a complete dropout? That's $1500 worth of ECM and careful packaging.

Any sources you know?

You can buy a brand new PCM and harness from GM Performance Parts for $1130.
http://paceperformance.com/i-6255503-19258270-cpp-ls3-controller-kit-for-ls376-430-contains-pre-programmed-ecu-harness-sensors.html

Keith Tanner wrote: You can buy a brand new PCM and harness from GM Performance Parts for $1130. http://paceperformance.com/i-6255503-19258270-cpp-ls3-controller-kit-for-ls376-430-contains-pre-programmed-ecu-harness-sensors.html

I think you missed the point.

I can buy an engine for $1k. I can buy the wiring harness for $200. I can buy an ECM for $90. Why are the dropout swaps $2500?

Does that $1K engine include accessories; A/C, alternator, power steering, etc.? When I've shopped for & bought other engines that weren't "drop outs" they were rarely much more than the long block.

buy this then scrap what you dont need

Be careful with that 99 truck - all 99s and some 00 6.0L LS truck motors used Iron heads - and you want Aluminum heads.

curtis73 wrote:

Keith Tanner wrote: You can buy a brand new PCM and harness from GM Performance Parts for $1130. http://paceperformance.com/i-6255503-19258270-cpp-ls3-controller-kit-for-ls376-430-contains-pre-programmed-ecu-harness-sensors.html

I think you missed the point. I can buy an engine for $1k. I can buy the wiring harness for $200. I can buy an ECM for $90. Why are the dropout swaps $2500?

So... just buy them individually and quityerbitchin.... its not as if they are matched at the factory. Some assembly line person grabs parts from a "bin" and installs them in the car/truck.

F1jim64 wrote: Be careful with that 99 truck - all 99s and some 00 6.0L LS truck motors used Iron heads - and you want Aluminum heads.

It really doesn't make a difference. The aluminum ones are nice, but not a must have. Any of the 6.0L's make easy fantastic power.

And then bolt on a set of L92 heads!

curtis73 wrote:

Keith Tanner wrote: You can buy a brand new PCM and harness from GM Performance Parts for $1130. http://paceperformance.com/i-6255503-19258270-cpp-ls3-controller-kit-for-ls376-430-contains-pre-programmed-ecu-harness-sensors.html

I think you missed the point. I can buy an engine for $1k. I can buy the wiring harness for $200. I can buy an ECM for $90. Why are the dropout swaps $2500?

When we have bought drop outs, it came with practically everything. Accessory brackets, water pump, alternator, P/S pump, etc. You know, the 10% of what you see in a project that is in reality 50% of the cost. Also, they have come with the TAC module and the accelerator pedal. If you can get this, you don't have to rig up a throttle cable and buy a throttle body, you just bolt the pedal to your firewall and plug it in. $2500 for an LQ9 dropout is a really, really good deal.

OEM computer all the way. It's very, very robust and tunable with various software packages. We use HP Tuners which is a little expensive but you can make some of that back by tuning other peoples' cars. But really, if you're doing a bolt in swap, you just need to disable the anti-theft and maybe eliminate some emissions-specific tests if you are doing a pre-emissions swap. Or you can leave it all on and have a nice emissions-friendly swap for next to no additional effort.