Vortec 454/4L80e HD swapped 1999 Tahoe OBS

Discussion in 'Under Construction' started by bigfootchiro, Aug 27, 2017.

6.0 Carb Conversion or Stay EFI?

Poll closed Jan 13, 2019.
  1. Carb Conversion

    0 vote(s)
    0.0%
  2. Stock EFI

    100.0%
  1. bigfootchiro

    bigfootchiro Full Access Member

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    As suggested by @Tonyrodz , I'm going to do a build thread on my 99 Hoe. I've already done a few things, but I will start with the LS swap in this thread.

    So I've decided to pull the trigger and do a 6.0 swap. I've done research, but still have questions. First off, I'm going to keep the 4L60E that I have til it blows, then either build it further or swap a 4L80E (or a 5 spd upgrade). I'm not 100% sure what my trans is built with; however, the previous owner said "it's built". We all know how that goes...

    I bought a 2005 6.0 from a Yukon, with all accessories including harness and PCM. Will the PCM need to be retuned, since it was made for a 4L65E, or are they practically the same, besides beefier internals?

    The engine is going to get torn down, dipped at the machine shop to have it cleaned, inspected and all seals replaced. The heads will be getting some work done to them, along with a new cam and springs. Should I go with a custom cam, or does anyone have any suggestions? I have stock stall converter, 3.73 gears and 35" tires. Looking for a decent lope at idle and good fuel mileage. By good, I mean currently around 12-14. I would like to stay in this range, if possible. I've looked into TSP220, 225/236 Hot Cam, BTR Stage 4 224/230, and many more. I'm thinking the larger cams may bring the powerband too far up in the RPM range for my gearing/tire size/stall; however, correct me if I'm wrong. I MOSTLY daily drive, with occasional towing.

    Also, any suggestions on head work for the stock heads besides a spring upgrade? Porting, decking, etc.

    All work will be happening in my friend's shop who builds race cars, so access to tools will not be a problem. They will be doing most of the work, but I will be involved after hours when I'm done at the office and on the weekends.

    It's going to be a fun project, and cannot wait for it to be done! Any other help and input for this swap would be appreciating, thank you!
     
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  2. bigfootchiro

    bigfootchiro Full Access Member

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    120K miles on this baby!



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  3. Snowbound

    Snowbound Full Access Member

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    Looks like the start to a great project. My 99 was just about to get the LS transplant as well.

    IMG_8957.JPG

    I pushed that old 350 as far as I could.

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    I picked up a 6.0 from an Escy that was wrecked. But it went into a buddy's GTO.

    7E0A146A-34F2-47BE-A6CA-2CB2A280E129.JPG

    Since I was going boosted I decided to get a lower compression 5.3 engine.

    608342AC-2B37-4C0C-A741-B5A08DB1377C-3701-000005F8764561AB.jpeg

    That project got scrapped. As much as I wanted to do it, I decided if I was gonna build another rig with some serious power I wasn't gonna have it in a 6000lb vehicle.

    As far as the 4L60, it should be ok for a little while. If it's truely built then you'll be ok. Keeping it cool is the key. If and when you decide to step up to the 80e, there's just a few pins that need to be switched around in the trans connector and a wire added for the input speed sensor. Easy job. Plugs are the same. It will require some tuning to go from the 60 to the 80 but it's nothing more than some segment swaps in the tune. Being a 99 Hoe everything else should swap over nice and easy. The PCM will work with your heater and ac controls and will run your instrument cluster without a problem. One thing you may need to do is tap into your PRND21 for your cluster. The 99 goes right from the switch on side of trans to your LED readout on dash. The new 05 PCM gets that input from trans and then relays it to digital readout on cluster in the 05 which you won't have. Not a big deal, get yourself a schematic for both vehicles and it's as easy as soldering and heat shrinking a few wires together.

    Looking forward to following along with the build. Best advise I can give you, don't rush it. Don't tear your engine out until you have everything ready to go. It'll help you avoid what most guys run into and hitting a wall and losing all motivation. Stay focused and source parts by searching and reading everything you can. There's a lot of good people on this site and they are more than willing to help you spend your money. Lol.
     
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  4. bigfootchiro

    bigfootchiro Full Access Member

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    Thanks for the advice @Snowbound , that looks like a great project as well you got going there! I will make sure to get both schematics and match everything up. The biggest thing I'm wondering about are the coolant hoses. I'm going to get a new water pump and idler pulleys, but do you need to make custom coolant lines, or do they match up pretty well if bought for the 2005 6.0 Yukon (that's the motor I'm using)? Also, the AC lines, but can those be had out of a 2005 and installed, or do they need to be custom/modified? I know a lot of guys are running that custom bracket, but wondering if I can get away without it.

    Haha, yeah, can't wait to have people help me spend some money! Keep the ideas coming! Here's one to start... ideas on cam grind specs for my setup? Also, does anyone have a full gasket set for this motor they are will to part with?
     
  5. Snowbound

    Snowbound Full Access Member

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    For top coolant hose I have a part# 71576. The bottom hose can be taken off the donor vehicle or part# 71428. As far as steam vent, you can tee into large 3/4" hose close to the heater core. People argue this but I've seen plenty do it and worked fine.

    There's a kit for the ac compressor that I see others used, look up LS Kwik ac kit. It uses an 80's style R4 compressor, but I didn't like it. Also seen where someone took the R4 compressor bracket off an 80's Camaro and made it work. Can't seem to find pic to share right now. Vintage Air also has what's called a front runner application. It's a pricey sucker at $2700, but it looks awesome.

    IMG_9324.JPG
    Lextech (Jeff) makes a bracket that will mount your ac compressor on the drivers side just as the stock one did. I started making my own just like his, never finished it because I needed compressor sitting on engine to line up pulleys. You should email him, he can give you price on ac bracket and also he can send you all the pinouts needed for your swap. Jeff is a great dude. Be patient tho, he gets tons of emails, mentioning your interested in his ac bracket might get you bumped to the top of the list. [email protected]. Any other bracket out there other than Jeff's will require you to get custom lines made and most require a different compressor. So Jeff's kit will save you in the long run. I'll post what pics I have of his kit.

    Not sure if you have a returnless fuel system or not but if you do you can get a 2000 Corvette fuel filter. It has a built in regulator. Your stock pump will work just fine also.

    IMG_9325.JPG

    Back to trans, you may need to get a spacer for the snout of your convertor. Also just so your aware, there will be 2 bellhousing bolts that you won't use. One is the very top hole where your tans doesn't have this and the other is, well you'll see on the back of the engine where it's not drilled and tapped. As for the convertor bolts, I've seen most guys oblong the holes in flexplate and it worked. You can get a new flexplate for that application, they aren't expensive.


    Another thing- if you're going to keep the stock exhaust manifolds, which really aren't all that bad in the first place, go find a set of head pipes from a 2500HD truck. They will fit right in place with minimal modifications, and they are nice stainless mandrel bent pipes. They run all the way to the back of the transmission on the passenger side and attach to the bracket on the side of the transmission.
     
    Last edited: Aug 28, 2017
  6. bigfootchiro

    bigfootchiro Full Access Member

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    Wow, thanks @Snowbound , that's a lot of helpful information! Definitely going to come in handy. I've heard of Jeff, after reading through so many forums and threads, but wasn't sure how to get a hold of him, so thank you for that. I do believe I have dual fuel lines. The flexplate I have on the engine now is dished, not flat, so that SHOULD work, correct? With the exception of having to oblong the holes... Actually, I stopped after that last sentence and did a quick search...

    http://www.crateenginedepot.com/LS1-Flexplate-Spacer-12563532-P10346.aspx

    This says the dished flexplate will work on the 4L60E and LS1 without an adapter. Now are they talking about the real LS1 346 OR the generation of LS motors? The adapter isn't much if I end up needing it, so no biggie there.

    Would you use the stock manifolds with head pipes over a set of headers? That's one thing I'm debating right now.
     
  7. Snowbound

    Snowbound Full Access Member

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    I would think that the flexplate will work for the 60 regardless what LS you have. Don't quote me on that. It may have something to do with the end of the crank on the LS1. That should be easy enough to find out with a quick search.

    As far as headers, that's totally up to you. But I highly doubt your gonna feel any difference in your assdyno. The stock manifolds are of a header design and actually flow really well. Many people use them on turbo engines where flow would be more important than a N/A engine. I'd use that money on something else like cam.

    Brings me to my next point that I didn't touch on before, camshaft. You can see all types of numbers that people will throw at you regarding lift/duration/lobe separation. My advise, don't take people's advise. Call a professional. They are gonna ask you many questions as far as vehicle weight, gear ratio, tire size and so on. They will tell you what the best cam is for your particular application. Do not get scared if they mention custom grind. My last custom grind camshaft was only like $26 more than an off the shelf unit. There plenty makers out there. Some are more conservative than others. Comp Cams is one of them. Isky and Lunati are two that won't be so conservative but they will still give you choices. An email can take some time to get you to the end results, a phone call to their tech line is best bet. Then you can compare the numbers that they tell you and then make your determination based on your preferred RPM range and of course, price.
     
  8. Snowbound

    Snowbound Full Access Member

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    I'm gonna apologize a head of time here. I work midnights, most times 11pm-11am so I might not comment back right away or I might post back in the middle of the night while I have a little down time at work. I apologize because my down time at home is getting few and far between with my wedding coming up on the 9th. I'm struggling to get things done and in order in time here but I assure you, I will do my best to get back to you as time permits. I'm gonna enjoy watching your project take shape and I'll be kicking myself in the arse for getting rid of mine.

    Your off to a great start, ask questions, research and search for parts. The more prepared you are, the easier this is gonna go. Plenty of information out there to be had because people have put these LS engines in everything, prob even lawn mowers.
     
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  9. bigfootchiro

    bigfootchiro Full Access Member

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    Hey no worries, I appreciate all the help you've given me thus far, and I appreciate you taking the time out of your day to get back to me. I noticed they were a header design, but wasn't sure how well they flowed, so I will definitely keep those on for the time being! And I will definitely call Comp, Isky and Lunati. How about Vinci? I've heard good things about them, but not too much, whereas I've heard Comp and Lunati all the time. Emailed Jeff, as well, so just waiting to hear back from him

    Btw, CONGRATULATIONS! 11 more days :eek:! How's your gut right now?
     
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  10. Snowbound

    Snowbound Full Access Member

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    Wouldn't hurt to try any and all cam manufacturers. Jeff will get back to you, just might take a day or two. And thanks, I'm good other than the stress of it all. This is my second so I already have my practice marriage out of the way. :) It's the planning, dealing with family, and the cash I keep having to fork out that's stressing me out. But like you said, 11 more days and all this crap is behind me.
     

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