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8.1L or 6.0L?

6.0L, or 8.1L?

  • Total voters
    81
My 95 K2500 was a TBI 350/ NV4500/ 3.73 rig and it was a DOG. The gearing, coupled with the 170K tired motor ran fine w/o a trailer, but once you hitched up anything at all you really felt it. I loved the 4500 though. My current K20 has a mild q-jet 350 and a SM465 with 4.10's and it flat out screams compared to the 95, but it really turns the R's on the highway and loves to drink gasoline. I'm considering updating the drivetrain down the road, but the more I look at the time and money I'm going to spend to do a drivetrain swap, the more I think I'll just buy a plain jane new rig with the 6.0/ NV4500 and keep the K20's original drivetrain. At any rate, it'll be awhile before I do either one. Hell, IDK, I have trouble leaving well enough alone as it is.
 
bowtiepower00 said:
I have trouble leaving well enough alone as it is.
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Ha, you're telling me? :haha:

You're talking to a guy who started with a 2wd 3/4 ton GMC with your basic 350 / TH400, reasonable option load. Now he has a 4x4 3/4 ton 4x4 GMC with a TPI 355, SM465, 205, Suburban tank under the box, and just about every option ever offered on these trucks, less AC.

Heck, I've never once taken the TPI 355 out for a spin on the road yet, and I'm already shopping for a new engine :doah:

Truth is, as I mentioned above, I'm not particuarly excited about tuning the engine up, just to get an engine that'll never perform to my expecations. I'd far rather just bail on the TPI, and go newer. I'm sure I can make at least 60% of what I've got into the TPI back.... ( :doah:)

But yeah, I'm still in the starting stages of all this... My truck will most definitely be getting the NV4500, and the NP241 before summer, but I'll probally leave the TPI 355 in there until the next winter. I'll have all summer to earn money, and research, so I can get swap done properly, and quickly :)
 
Not sure why you "have to" keep the instrument cluster... I don't see why you can't just hook up your stock oil pressure, and water temp gauge to whatever engine you drop in your truck even if its a duramax.. what else is there that you really need to monitor? volts/amp meter is easy enough. maybe the glow plug light or something?
And as for a tach, i think '02 and earlier genIII's will work with a 4 cylinder tach, but '03 up needs some special tach converter that i have still yet to find and hook up.. I just shift by ear when it hits the rev limiter. :wink1:
 
I was reading up on the 6.6L swap that the fella on TheDieselPage.com did, and he mentioned that the instrument cluster was a required component in the network in the truck, and that it wouldn't run without it.

Seems a bit crazy to me, if you can eliminate other parts of the network, why not the instrument cluster?

Prehaps his information is simply just that outdated? Electrically speaking, this is the only part of the duramax swap that concerns me, esspecially with bolting it up to an NV4500 / NP241 combo. The rest of the swap shouldn't be that bad either, exhaust might be a bit of a pain, but its not that big of a deal...
 
What year duramax are we talking? any of em?
I'll look into that for ya when i get a chance.
 
Doesn't matter to me :) I'd prefer a newer one that is out of the injector problems era though. Heck, if you can point me to where I can find wiring diagrams etc, I'd love to do some in-depth research into exactly what it'll take to make this happen. There is a ton of info out on the web about doing gas swaps, but next to nothing on the duramax swap...

Either way I go, gas or diesel, I intend to make a pretty in-depth writeup on it in nearly step by step form outlining problems and their solutions for anyone to access. Also include all the information that I used in a resource library, if possible

I don't think these swaps are really as bad as a lot of people make them out to be. It seems the only real expensive part, less the purchase of the donor truck, is the ECM re-flashing...

Thanks for all your time and help here Ryan, I really appreciate it, esspecially with the number of people that must be asking you questions / for wiring diagrams etc :)
 
There's a guy on dieselplace.com that swapped a '02 Duramax into a '87 K30. He didn't have to swap instrument clusters at all. You should go on there, find his profile and PM him about it.

Scott
 
well, after much debate, I've decided that I won't be swapping in either a 8.1L, or a Duramax. If I go diesel, it'll be a modified 6.5TD. If I switch out to a gasser, I'll run an LQ9 6.0L
 
8.1 for me

I have the 6.0 now in my truck and I am looking for an 8.1 burb to upgrade to. I am lucky to get 12MPG's on the highway in my 6.0 so they mileage difference of the 8.1 is not an issue.I want the extra torque/towing benefits of the 8.1. Just my .02
 
I kinda wanted the 8.1L, but there are a few things that chased me off. First is some mechanical concerns, a lot of slapping pistons, and burning oil happening on those things. Second is how hard they are to find, I could only find one for sale in Canada, and that was over in Montreal...

Third, you can get 16 mpg out of a 6.0L, if you drive it nicely, and tune it up better by getting rid of the torque management crap.
 
gmcjimmy88 said:
I have the 6.0 now in my truck and I am looking for an 8.1 burb to upgrade to. I am lucky to get 12MPG's on the highway in my 6.0 so they mileage difference of the 8.1 is not an issue.I want the extra torque/towing benefits of the 8.1. Just my .02
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THE BIGGER THE BETTER!!!
:eek1::eek1::eek1:

Size does matter!!
:waytogo::eek::cool:
 
First off there is no replacement for displacement. If you're gonna do an engine swap and these are your choices then go the 8.1 for sure.
PM RyanB, he has done a swap with both of those engines.
 
It wasn't when I posted this 4 - 5 months ago :D I found a great deal on a 5.3L, and figured that if the one in my mother's Tahoe goes like it does with an auto, and torque management, it'll be fine in my 3/4 ton with similar gearing, a 5 speed standard, and a performance tune / Torque Management deletion :D
 
Any updates on this? I am looking at all my options and one of these seems like a good choice. Thanks
 
Strange, thought I posted an update in here just a few days ago, lol

I had a good low mileage 5.3L here, but sold it way too cheap with the promise of a 6.0L I could buy for as much as I sold the 5.3L, but the fella with the 6.0L fell through on me, so now I am back to a carbed 350 with an SM465. I didn't loose any money on the deal, but I did loose a perfectly good engine :doah:

If I do a swap, it'll either be one of the new 4.5L duramax engines that are being released next year, or an 8.1L.

I know of a relatively local low mileage 8.1L, but the guy wants 3500 for the thing, which is about 1000 more than it is worth. He won't budge on his price either, so I don't think I'll be getting it.

So, update is that I'll be sticking with the 350 for a while. My order major purchases for the truck is going to be body work first, then an NV4500, then a new engine when I can afford it.
 
i would go 6.0 for sure if not 5.3. SO much after market for them as opposed to 8.1

here is a place where i am going to buy my 5.3 from when i do my swap for my blazer
http://stores.ebay.com/bowautoparts

or you can always pick up a 4.8 or 5.3 and just make it an iron block LS1 5.7

if you do go with a 6.0 though make sure you get a 01+ 6.0... 99-00s were all iron heads and the cranks were to long cause the spacer was built into them for the 4L80E.. not sure how that will work wit you NV4500. if you get an 01+ the spacer is removable so you can just use the crank that comes wit the motor
 
5.3s aren't bad motors at all once you toss a small cam in them and have a good pcm tune with TQM removed, added spark, etc. I seriously have under $2,000 into my cammed 5.3 in my blazer to get it running. I NEVER could have built my 350 to do what the 5.3 does as cheap or efficiently as the 5.3 does. I have a 80e behind it and it totes the blazer around REALLLLLLL well. It pulls so much stronger than all the stock 1500s with 5.3s that its ridiculous...drove my dads 00 ext cab 5.3 2wd thats totally stock and it was a DOG. Mine just $hits and gets! wiring on them is REAL easy too. Using a full complete engine/trans stock wiring harness, there is 7 wires to hook up to the pcm to make it happy (4 grounds, pins 1 and 20 on red and blue, 2 12v+ constants, and 1 key on 12v, forgot the pins for those...), hook up the red wires in the harness to keyed on power (can use stock fuse box if you get your hands on it) and ground the black wires in the harness. Remove VATS in the PCM, give it adequate fuel pressure and it runs. You can buy the motor mount adaptors on ebay and whatnot for about 45$ shipped and it allows you to drop the motor in to your stock genI/II mounts.

Now with all that said...i would not doubt that a properly set up/tuned 5.3 could tow well. The stock tunes are so anemic that its crazy and a cammed 5.3 with good tune should outpull a stock lq4...even with a crappy tune i can spin my 37s over with 513s and my bed half full of crap for 15-20 feet. Also, you can always do what im doing, find a cheap 5.3, install it, run it for a while, then casually look for a 6.0. Once i find a cheap enough 6.0, ill throw it in, with a cam and whatnot, and call it good.

Personally, i still think you should go back to the LSx small block idea. i had essentially 400$ into a complete motor that i could have swapped into any 99+ silverado, hooked up wiring and fuel and it would have run. You can get good PCM tunes for 200$, exhaust work for $200, and redo the wiring harness yourself. a couple hundred dollars on odds and ends and that is about it.
 
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