LY6 6.0 into an '85 C10 Suburban

[SBTork]

This is my DD, it's a lowered '85 C10 Suburban, I will be sure to post pics once this project gets underway. My plans are to upgrade to a nice solid LSx drivetrain for the purpose of DDing it. Maybe some weekend towing and mainly just crusin'. Maybe the occasional 1/4 mile pass but MAYBE once a year, just for fun.

I am in search of some advice/guidance on this project. I've done a lot of research on gen3 LSx swaps but nothing on gen4 LSx swaps. I am sure most will crossover but I have a few concerns. I will start with what I THINK I know.

I should upgrade to a 87-91 Suburban fuel tank and fuel sender. To gain baffles in tank, not a required upgrade but i've heard it's worth while. I need a new fuel pump that would be a direct replacement for a newer vortec GM truck, acdelco pn ep381. I am unsure if I need to use the 'vette style fuel filter/regulator or if I can use something else. I assume I should just run all new fuel lines front to back to avoid any future problems. I have a set of fuel injectors and rails from a 2004 Tahoe with the flex fuel 5.3, will those work with this LY6?

Can I use my stock 700R4 or should I try to find a newer 4L60E? I would run a 4L80E but I am not sure I need it and don't really want to put up with the power loss. This engine is always going to be N/A so I think a slightly modified 4L60E would do just fine.

The PCM/ECM's on these are unique from what I know. I know they don't use a seperate electronic throttle module like the up to '06 trucks do. The stock '08 system goes from the gas pedal straight to the PCM/ECM? Is that part of the engine wiring harness, or something else?

I am collecting parts for this swap over winter and plan on doing the swap early next spring, I just want to get everything lined up and make sure I have a good understanding of it all before I tear into it. I am sure more things will pop into my head as I go, but if anyone has any tips or suggestions please fell free.

[68GMCCustom]

Have you already got the LY6? This is the same motor I'm using...tho I'm going carb'd with a MSD box firing the coil packs. I also ditched the VVT stuff and am running a Comp LSr cam and .650 springs. I am also using a 200-4r...and you can use your 700R4...but you might want to rebuild it with HD parts.

Big differences are the LS1 genIII setup was a 1x cam gear and a 24x reluctor wheel
LS3 genIV uses a 4x cam gear and a 58x reluctor wheel. If you're keeping the stock efi setup and ECM, you won't have to worry about it. The gen III motors use cathedral port heads...where as the genIV motors L92, LY6, LS3, etc. have rectangular intake ports. So they use different intakes to fit the rect. port heads...and are not genIII compatible. Meaning you can't use a catherdal port genIII intake on a rectangular port genIV head.

[SBTork]

Thanks for the reply. Yes, I am keeping my set-up fuel injected. And yes, I do have the engine, got it about a week ago. I have yet to clean it up or anything but just looking to gain knowledge and collect parts for a few months. So, basically everything to do with the upper end of the engine, harness and electronics should be '07-UP truck stuff, correct? I.E. injectors, TB, fuel rails, etc?

[68GMCCustom]

I would think so...or you're likely to run into compatability issues.

[foamypirate]

Woo hoo! another LY6 swapper. That is what I am planning on swapping into my 87'. My biggest debate is whether or not to keep VVT. Are you planning on keeping it?

[SBTork]

Originally Posted by foamypirate

Woo hoo! another LY6 swapper. That is what I am planning on swapping into my 87'. My biggest debate is whether or not to keep VVT. Are you planning on keeping it?

No, I plan on keeping it somewhat simple and getting rid of the VVT. I cannot wait to get it in there and drive it. What are your plans for the swap in your truck?
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[clinebarger]

Originally Posted by SBTork

Can I use my stock 700R4 or should I try to find a newer 4L60E? I would run a 4L80E but I am not sure I need it and don't really want to put up with the power loss. This engine is always going to be N/A so I think a slightly modified 4L60E would do just fine.

There is no practical way to operate the 700R4s throttle valve cable on a "drive by wire" engine. A built 4L60E whould be fine. A 4L80E is overkill for a 1/2 ton suburban.

[SBTork]

Originally Posted by clinebarger

There is no practical way to operate the 700R4s throttle valve cable on a "drive by wire" engine. A built 4L60E whould be fine. A 4L80E is overkill for a 1/2 ton suburban.

Awesome response, that is exactly what I was hoping and thinkng. Thank you.
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[68GMCCustom]

I thought if you got rid of the DBW and went DBC (along with the getting rid of the VVT) that there were brackets and cables available to use a 700R4? Not sure how you'd best make both these ECM changes though. Use an LS3 ECM? Surely you wouldn't have to swap it to a genIII PCM and related hardware.

Not sure I'd get rid of the VVT tho if you're keeping the EFI. And I'd probably also go with a 6L80 if I was running EFI with ECM control and had a genIV motor... capable of running a 6L80e.

[foamypirate]

Originally Posted by SBTork

No, I plan on keeping it somewhat simple and getting rid of the VVT. I cannot wait to get it in there and drive it. What are your plans for the swap in your truck?
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Personally, I'd find it simpler to leave the VVT in. The computer is already setup to control it, and it's already there. Why tear into a motor and forfeit the benefits of VVT? If you have a cam swap in your future, it would be easy to remove it at that time, if you wish.

My plan is to keep VVT on my LY6. I'll be installing a Mast VVT cam later on; hard to pass up a strong bottom end and still being able to rev it out and make gobs of power. I've heard the LY6 will crank out about 410HP with headers and a tune. I'm also planning on running a 6L80E. I'll be doing my harness through Speartech, as they have experience with tuning the E38 ECMs and 6L80E transmission computers. The primary reason I want the 6L over the 4L is the gear ratios. My truck currently has 3.08s out back, and I'd rather not change them out. With the 6L, I have that deep ~4:1 first gear to get me moving, but I'll have an awesome cruise RPM with the double ODs and 3.08s. I *may* gear up to a 3.23 if I don't find the combination pleasing off the line.

[sdwolff98]

How is that swap going? I am about to start working on mine. I got lucky and found a complete L92 and 6l80 package here in plano for a grand and am paying it off currently. I will be looking for the harness and such come early feb and march while my truck cab is at maacoo getting some work done to it. Tossing all that into a 64 3/4 Gmc with 4.56 gears might have to tone down the 3/4 hauling drive train for the trans but will see late this summer. Any other places besides mast and speartech for harnesses? I am kinda looking around since I have found the facotry harnesses new for pretty cheap about 300 a harness from oem supplier.

Thanks
Sean
plano texas

[SBTork]

thanks for the reply Sean. Your project sounds awesome, make sure to take plenty of pictures of any and all progress.

Mine on the other hand has taken a turn. I wound up trading a local fellow my gen4 6.0 for an old 5.3 and some cash. Main reason being, I was not able to do the swap in a reasonable amount of time and the 6.0 would've been sitting for at least another year if not two. So, instead of letting it sit, I opted to trade for an older 5.3 and some cash. I am more comfortable with the slightly older gen3 stuff and the 5.3 can sit and wait. I plan on swapping the older 5.3 in during the summer of 2012, we'll see. I may tear into the engine yet this winter just to get a plan for it because I'd like to put a different cam in it and maybe some more parts. Time will tell.

[sdwolff98]

Well that works ... I am thinking of the speartech harness setup myself since he has figured how to reprogram the tap shift center console handles to work like the corvette paddle shifters I have already located the harness and engine computer so he can reconfigure everything and make it work for me. Will be loading some pics on my website as soon as I get the engine home come mid january 400$ to go and the fun begins ..

Sean

[SBTork]

I have heard great things about speartech. I also once heard of a guy on ebay that makes custom harness's for LS swaps, he builds off of what you have and want. I am not sure if he is doing the gen 4 stuff yet or not. At least with speartech you know they're going to stand by their product. I may be going through them once I start mine as well. Are you going to start a build thread soon on yours?

[sdwolff98]

Hi there,
Yeah as soon as I get the engine/transmission home and the computer fixed will be starting a buildup thread on this truck. Will be really rolling once i get the cab and rear bed off for body work then I can really get the frame fixed for it. Plus will be able to get some good shots of the brake mods I am doing to this ttruck as well.

Sean