Need a little bit of direction!

hello, let me first start off by saying that i am very very new to the whole concept of new school electronic engines, and this forum alike, i have looked but cannot find what i am looking for although im sure its on here i was hoping someone could point me in the right direction, i have a 1997 GMC sierra 1500 2wd with the 5.7 vortec, i was recently given a 5.3 vortec engine, pcm, wiring harness, trans, and anything else i need off the truck as it was wrecked pretty bad, i would like to do the swap and i have been reading and about 50% of what im reading tells me my stock vortec pcm will run the 5.3 and some things say it will but i need to have it tuned again very new to this world, so has anyone does this conversion that can tell me if the wiring harness from my stock vortec will run a 5.3 or what i have to do to make it work run dual pcms or just the new also if it helps the donor truck is a 2002 Chevy it is still cable drive and although i have not made 100% sure im pretty sure it has the 4l60e in it as well as my truck, i would like to keep my trans in my truck if possible as it is a brand new trans with less then 3k miles on it again im sure this information is on here but i couldn't find it so if someone would be so kind as to point me in the right direction i would greatly appreciate it

You don't need to run two PCMs. You can use your 97 harness with a bit of reworking and the addition of 10 wires -- Or, I'm sure Nelson Performance (The owner of this forum) can supply you with a harness. Your 4l60 should be fine behind the 5.3

Jeff

I built my first 97 in 2005 installing an 02 LS6 and used my factory harness and added wires like Jeff said. I was able to make everything work including the gauges using is HP tuners and the 02 Ecm. If you don't like spending time reading schematics and tracing out wires from both vehicles do what Jeff said and talk to Allen and get you a harness. You can make that 5.3 scream if it's a regular cab and add a cam and 3200 stall in the transmission. You can find diagrams in the stickies but you'll nead the c-100 diagram for the 97 so you'll know which wires to remove from the 97 harness. It really sounds more complicated than it really is. Once you get the motor in then the fun starts.

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Originally Posted by NITROUS

I built my first 97 in 2005 installing an 02 LS6 and used my factory harness and added wires like Jeff said. I was able to make everything work including the gauges using is HP tuners and the 02 Ecm. If you don't like spending time reading schematics and tracing out wires from both vehicles do what Jeff said and talk to Allen and get you a harness. You can make that 5.3 scream if it's a regular cab and add a cam and 3200 stall in the transmission. You can find diagrams in the stickies but you'll nead the c-100 diagram for the 97 so you'll know which wires to remove from the 97 harness. It really sounds more complicated than it really is. Once you get the motor in then the fun starts.

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Thank you for your information, Also thank you Lextech i appreciate both of your input i guess i failed to mention my plans, when i first bought my truck i paid 200.00 for it from my brother inlaw who had just spent 2000 having the trans redone at a local trans shop he was very angry and sold it to me on a whim, just so happens i had the money, well i got it tore apart and found the block was junk so not knowing any better and with a extreme lack of research (as you can tell im not making that mistake again) i assumes a SBC block is a SBC block and purchased a fresh rework from a 1972 camaro and bolted my vortec heads on it and the vortec fuel injection and it runs and i have been driving it this way for approx 1 year on and off, i dont drive it at all in the winter and i live in Michigan so thats 8 of the 12 months of the year (lol) but i have dependability issues, it starts every time but has an extremely low idle (3-400 rpm) if im lucky it stalls alot and it is TERRIBLE on gas from where i live to where my parents live is roughly 7 miles and to drive there and back uses roughly 1/4 tank of gas (yes i have looked for leaks non present ) the best i can come up with is the valves are opening at the wrong time as i assume perhaps the vortec cam and crank might be clocked differently then the old school so its having cam and crank correlation issues regardless my plan was to buy a reman vortec and stuff down in there and then my uncle who owns a local towing company was given a 2002 chevy from a accident with the 5.3 in it low miles and very light front end damage broke the fan shroud but that's about it i will be pulling the engine trans wiring harness and a few other things i would like to put the 5.3 in my 97 and leave it with a stock tune, i am not at this time doing this for big horsepower or to make it a hotrod or anything of the sort just a dependable truck with a little better gas mileage i am all good with reworking my harness myself and i am all good with adding the 10 wires Lextech mentioned and am ok with reading wiring diagrams and all that stuff i was looking for and hoping someone could advise given the options i want for my truck right now, if i run my stick vortec harness and pcm and rework the harness and add the ten wires will i need to have the pcm flashed? what would the 10 wires i would need to add be for, if this is already in a write up somewhere could you please provide me with the link or tell me how to find it, if its not any advice you guys have for me would be great, and i have looked into just buying a harness but unfortunately that is outside of my allowed budget at this time not that i dont think it would be easier but if i have to spend some time working on my harness to keep actual dollar amounts down thats what i am going to have to do, i also understand alot of you guys make money off helping people like me and dont want to do it for free, and im sorry for being the newb guy looking like im begging for answers for free but i am at a loss as to where to look for these answers on my own thank you all and anyone in advance for help i really appreciate it

PM me your name and e-mail address and I will send you some info.

Jeff

I'll chime in with my 2 cents to help out a new member (like I was not too long ago at all) and say that you're already heading in the right direction by ditching your old 5.7 and going with a 5.3....anywho, after completing my swap I had one regret and that was that I didn't put a cam in when I did the rebuild and to be honest my funds were stretched way too thin and the truck is my daily so I had to get the swap moving double time. If you can't afford a big flashy new cam and valvetrain setup that's totally fine because a used LS6 or LS2 cam will bolt right in with no other mods except the tune to match. Now, I put a LQ9 6.0 into my truck and it already has a decent amount of hp and torque especially with the longtubes and tune so I'm not necessarily missing out on any power but I'd like a little extra to put me over the 400 mark in torque considering I pull a '77 Airstream around and I need a little more on the bottom end especially for hills. If you do nothing else to your engine get a cam and any other LS6 parts your wallet can afford. Also, I almost forgot to mention that I bought an A/C relocation kit from Jeff (Lextech) and I'm extremely happy with the fit and quality of it, (well worth the purchase) so if you have the sanden style compressor, you should also get that kit. And when you pull the engine measure the distances between the flexplate and block on both the 5.3 and 5.7 to make sure you don't need the space/adapter because I didn't on my 6.0 but I heard it might be different on the 5.3

Just an update the swap is done and it is running, i am having a small issue i believe to be wiring related, started it up (FIRST TRY i might add) surprised my self to be honest because i had never done a swap like this before but its throwing me out a p0200 (injector circuit malfunction) and p0300 (random multiple misfire) know i know that p0300 can be caused by p0200 so i am trying to sort that out i have tried swapping parts (coil, plug, plug wire) nothing seems to change it but at random it will switch from number 6 misfiring ALOT to numbers 2 and 8 and then 6 is fine, i have wiggled wires checked grounds(although im still not convinced i didnt miss one) checked grounds at pcm everything i can think off anyone with any advice even if its bad advice i would be grateful