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8.1L or 6.0L?

6.0L, or 8.1L?

  • Total voters
    81
Russell

Russell

3/4 ton status
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Location
Rocky View County, AB
Hey guys!

I've just got my TPI up and running, and I'm already looking into a newer engine, LOL

I've got my grubby mitts on an NV4500 / pass drop NP241, and will be putting them behind the TPI 350 for now, but in the future I'd like to swap in either an 8.1L or a 6.0L

My truck will not be a daily driver, and will primiarly be used for Sunday morning cruising, or driving to the lake and back with either a few quads behind it, or the boat. I will regularly be using it to haul a 1000 gallon water tank on a trailer as well.

I know not a lot of guys have swapped them around yet, but if you were to swap, which would you go for?

I kinda want the 8.1L, for the extra torque, and for the ability to brag that I have a 496 in my truck :) However, I've read that they occasionally suffer from excessive oil consumption, piston slapping, and that they all are drive by wire units (I hate the drive by wire pedals, way too soft)

The 6.0L would require me to fab up some engine mounts (appears pretty simple), but its possible to get them with cabled throttle bodies, and they are far more common.

Either way I'd aim to find a totalled truck so I can get everything off it, and pull it myself so I don't have anyone to blame with regards to cut wires but myself. I'd pull everything from the exhaust to every last little hose.

What would you guys go for? Anyone here perform either swap and have any tips or advice?
 
I have the 6.0 and like it so far. It has the piston slap, and prolly has had for the 90k miles that it has on it. I'm putting some Lucas oil treatment in now, heard it gets rid of the slap noise. I only have about 1500 miles since I got my truck, but so far its about 12.5mpg.

Have a friend with the 8.1 and he loves it. Mileage is only 11-12mpg. He hasn't said anything about oil consumption and has had it about 2 yrs now. He pulls his bass boat with it mostly.

In my opinion, mileage is close to one another, so might as well get the 8.1.
Don't know about the drive by wire, so that could be a tricky fab job.

Also, the 6.0 is a 300 hp motor unless you get a newer one which is 345hp or so.
 
I *think* the piston slap/oil consumption issues were an early thing, you really don't hear about it on the new rigs like you did the first couple years they were out.
 
Both motors are excellent. The later years, '04 and up don't have the piston slap that a few of the earlier years had. I would say go with the 6.0 but you are referencing pulling a 10K trailer around regularly, so my nod goes to the 8.1L.

Now get this project rolling soon so we can see some pics:bow::bow:
 
Yeah, the heaviest load I pull will be the bobcat + flatdeck trailer. The machine weighs in at about 8000 lbs, and the trailer at about 2000 - 2500. Thats just over 10 000 lbs, which my truck's drivetrain should be just fine with, less the engine at the moment.

Apparantly the drive by wire stuff isn't too terribly bad to install, its more of a personal pereference to have a physical connection to the throttlebody, not that the stepper motor quits working at WOT or something...

Well, I think more than anything it'll boil down to which engine I find at a good price first...
 
Yo.
I have a 6.0L-Nv4500 in my tow rig and my bud kevin has an 8.1L-Sm465.
The 8.1L has more grunt down low for pulling trailers, my 6.0L likes to pull the hills at 4000+ rpms.
The 8.1L is a torque monster, but if you want some top end horsepower the 6.0L screams in the mid and top end of the power band. The 6.0L gets a little better gas mileage. If i was building just a tow rig, i'd go with the 8.1L, anything else where you want some rpms, i'd reccomend the 6.0L. :bow:
5.3's should be everywhere and fairly cheap. 6.0L's are a lot more desired so prices are higher, and a good running complete 8.1L is the hardest to find for a decent price.
Check out pacificfab.net ...give us a call, we have complete, low mileage, (4 wire hook up) GenIII turnkey engines in stock with a warranty available. :wink1:
 
I'd love to buy from you guys, Ryan, but the shipping from the states would be simply insane... You can be sure I'll be hitting you up for PCM work though :)
 
I would do the 8.1, since you're not going to use your truck all that much, and when you do use it your going to be working it. If you are willing to modify the 6.0, then you could get similar power out of the 6.0. You could get an aluminum 5.7 from a wrecked F-body and build it to save weight.
 
I suppose there is always the option of a Duramax swap too... Bit more expensive, but would certainly get far better mileage on the long trips to the lake :D

Again, I think it'll wind up being whatever engine is in the next wrecked truck I come across at a good deal...
 
If you take a 350 and put a decent cam, aftermarket heads, and manifold on it, and take the time to tune it, you'll have more than enough power. If you want more, throw a cast stroker crank in it and build a 383, or start with a 454. Either route would be much cheaper than a newer engine. A Duramax would be the cat's meow, but you're looking at several thousand dollars and a lot more work.
 
Yeah, I do have a reasonable 350, but it isn't very well built. There is no doubt in my mind that it'll last for a very long time, but none of the parts are really matched to eachother, and esspecially with the EFI on tops, it just is gonna take way too much work to tune up. I'd far rather just swap to a newer engine that'll run cleaner, make more power, use less fuel, and be way more reliable than the current TPI 350 will.
 
SierraClassic said:
I'd far rather just swap to a newer engine that'll run cleaner, make more power, use less fuel, and be way more reliable than the current TPI 350 will.
Click to expand...

But you are talking about an 8.1??

I seriously doubt a well tuned TPI350 gets much worse mileage or pollutes less than a 6.0, as a for instance.

Personally, it sounds like you are trying to find an excuse to ditch the TPI setup you spent time and money working. :) I know the feeling lol.

At least you can say (roughly, some exceptions of course) that any of the non 1st Gen small blocks have technological advances in their design that just wasn't done on the 1st gens. Bore, stroke, head design, and so on.
 
Yeah, if I had done my research first, and built an engine that the TPI would be happy with, I wouldn't even be considering an engine swap. However, I was younger, and far stupider, so I took a bone stock 350, put a camshaft into it, and called it an EFI engine.

That 350 really needs the compression ratio bumped up, some good heads, and a lot of intake work if I want to make the kind of power I was expecting the EFI to give me. It was an expensive lesson, but not all is lost on it, as I believe I can make a fair bit off the setup selling it as a complete bolt in type deal, literally. Only thing the new owner would need is an engine built for the EFI, and a fuel system. The rest would be there.

All this said, I don't intend to do this swap until next winter at the earliest. I'll need my truck this summer to haul quads around, and will fiddle with the chip and get it working the best I can. I'll be swapping in an NV4500 / NP241 this winter, so I should be ok for mileage, just not getting nearly the power I could.

Also gives me at least a year to hunt down a donor vehicle, and also any other parts I need to collect to make it happen. I plan to use an old cab to fab up all the wiring so when the time comes, I can literally unbolt the wiring, bolt it into my 80, then bolt the new engine in, and have it running within a week or two, leaving room for problems I don't forsee.
 
Ryan B. said:
I have a 6.0L-Nv4500
Click to expand...

What kind of configuration is it, and how well does it tow a fullsize truck on a trailer? Have you driven an auto to compare it to? Don't want to sound rude, I'd like to hear from someone who's got a NV4500 truck. If I were to get a new truck, it would be 6.0/NV4500 or D/A, and the D/A is a lot more money.
 
D-MAX. with some bolt ons, 500hp and 1000tq, while getting good mpg. what more could u ask?
 
Well, after much deliberating between the three engine possiblities, I've basically decided on the 6.0L to go with my NV4500 / NP241.

I ruled out the 8.1L primarily due to how many people have complained oil consumption and piston slap, along with how uncommon of an engine it is.

I then debated back and forth over the 6.0L, and the dmax. The 6.0L is easier and cheaper to install, but the dmax just has way more to offer. In the end, it all came down to the instrument cluster of all things, lol

The 6.0L can be made to run without the stock instrument cluster, while the 6.6L requires the use of the stock instrument cluster. Only way around that is to install a 95+ dash, or to somehow figure out a way to isolate just the info center display from the gauges (the part it is after) and retrofit it into my dash bezel somehow... Neither way is particularly easy, nor am I sure it is worth the effort...
 
bowtiepower00 said:
What kind of configuration is it, and how well does it tow a fullsize truck on a trailer? Have you driven an auto to compare it to? Don't want to sound rude, I'd like to hear from someone who's got a NV4500 truck. If I were to get a new truck, it would be 6.0/NV4500 or D/A, and the D/A is a lot more money.
Click to expand...

Its my own custom configuration in my "'84" flatbed. :D
I pieced it all together.
2004 6.0L drive by wire, custom machined & modified hayes scattershield, hydro slave cylinder bracket welded right to the scattershield, '95 nv4500, i notched the tailshaft housing, and finally a '90 round pattern np205 with a short 32 spline input.
i put a heavy duty towing clutch in it, since its mainly my tow rig.
I've towed 600 miles with a th400-np205 and now i've towed about 3000 miles with the nv4500 np205.
The 5 speed just kicks ass. The only time you're in 5th towing a k5 on a trailer, is on flat and level. i towed to moab and back (1000 miles one way) and tried to keep it in 5th most of the time.
Mines geared 4.10 with 33's so i could use some more gearing now, on the tough grades i couldn't quite pull 4th the whole way up, so down to 3rd gear and it'll pull 55+ up any hill at 4,000+ rpms and accelerating towards the rev limiter. :crazy: :D
The headers and 3" exhaust i put on the tow rig also help it go up the hills A LOT better now than before with stock exhaust and the auto.
I got averaged about 10mpg for the trip, barbastard with his stock '02 2500HD got 7.5 mpg for the trip, and was hurting on some of the hills 40-50mph.

Russ... Forget anything about the instrument cluster out of the 6.0L rig. Whatever your swapping it into, (2nd gen chevy truck) get the sending units for those gauges and figure out how to plumb them into the 6.0L. :thumb:
 
Ryan, why is it that if you do a duramax swap you have to keep the instrument cluster, but not with a 6.0L?

And, I may possibly have found a 6.0L donor, we'll see if things work out my way somehow :)
 
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