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SWAP ?'s *I will use this topic thru completion

mrfishaholic

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mrfishaholic Enthusiast

mrfishaholic

Posted
Posted

My life just changed and the swap isnt going to happen. BUT, if anyone reading this needs a Donor Truck there is one in PARMA Ohio, (the one I was going to use) for $2300.00 same price I was to pay for it. Please look at For Sale stuff on this forum for my post there as I have given his number and the ebay auction number in which I purchased it from him where you can see photos of the truck. The truck isnt pretty, but the drive train is intact. I had a buddy look at it before I bid.

 

 

Thanks guys for your willingness to work on this with me. Wife Says that I can get a new truck once we get through this life issue....

Supercop8100 Enthusiast

Supercop8100

Posted
Posted

Wow. You talk alot.

 

But to answer some of your questions....I would go with the K&N induction. Everything should work fine with the switch. Just make sure you get the Allison ECM from the donor truck as well, or you wont get out of first gear.

Larry Enthusiast

Larry

Posted
Posted

Mr. Fish….

 

You do not talk too much….you are just like me and use a lot of words to say what you want to say… fkm other members that only BUY trucks and have never have BUILT anything. I am into swapping late model powertrains too so I have a lot to say as well because there is a lot to talk about when doing something like this. This is not as simple as swapping a prefuel injected 250 6 popper for a carbureted 350 V-8 like our fathers used to do 20 years ago. Now daz you have to be an IT guy as well as wrench spinner.

 

Being that you have come out to say you have a complete donor truck of the same model year at your disposal makes a huge difference and will make this transplant much easier and less costly. It also makes your info request much easier to assist with as you seem to appear serious about this and not another new member high on a pipe dream for a big block or diesel swap.

 

I warn you that if you go through something like this on a late model truck it will not be worth anywhere close to book value if you every sell it once you start severely monkeying with the powertrain and differentiatating from the original powertrain no matter how OEM you make it appear, as it was certified by VIN with by GM and our Federal Government so I hope you are into this truck for the long haul. And depending on the state you live in and emissions regulations you are governed by this could be a huge and very costly headache…..mainly California and many NE states as well as some Texas cities. (The Ranchhand bumper is a clue you live in TX).

 

If the you realize what you are getting into and biased on what you have said in your other posts…here are my recommendations to work with the hardware you have on the donor truck……

 

1. Swap in the 8.1 to your existing 4L80E, tcase, etc and use a Suburban or Workhorse VIN to flash your current ECM for trans and engine VCI algorithm calculations. Benefit….big block, less HP loss due to Allison parasitic load, less wiring harnesses to deal with for the trans and tcase. Downside: lack of Allison bragging rights, gear ratio split, trans strength, need of 8.1L Suburban or Workhorse VIN or engine cal VCI number for the tire rolling diameter, gear ratio, emissions, etc.

 

2. Use the 8.1 and Ally, manual tcase that is in your donor truck. Benefit… you have all wiring harnesses at hand, sensors, crossmembers, accessories, ECM, separate Allison TCM, mounting bracketry, more reliable tcase, better transmission, etc. Downside: don’t really see any….but you will need to make a decision of either buying a Allison prep NV263 electric shift tcase (JUNK) to work with the chassis wiring harness or be a MAN and use the manual shift tcase that your donor truck came with, as it is much more reliable anyway. Assuming that your crewcab has a full center console being that it has the flitboy electric shift, you can always trim your center console to make room for the manual shifter and tactfully add some interior color vinyl fabric to fill any gaps between the consol and shifter bezel. It has been done by guys adding full center consoles to base model trucks with tactful success since 1999.

 

I would also recommend that you swap in the rear 11.5 AAM axle to replace your 6.0L 2500HD spec 10.5 rear axle if the axle ratios are the same. Of course, the drive shafts will need to be reworked if you go the Ally route as your builder is a CK25743 model and the donor is a CK25903 model.

 

I am doing a similar swap but on a 23 year older truck, which is actually much easier due to emissoins regs in my area. PM me and we can discuss further and spare the rest members of the TOO much talk…..

 

Quite honestly, I am not sure why anybody would spend the bucket loads of dead presidents to swap a 6.0L for an 8.1L on a 5 year old truck, as the 6.0 is actually faster and more athletic around town. If yanking trailers and the braging rights of having big pissers under the hood is your deal then the 8.1L is for you. Believe me….the 8.1L is NOT fast (I own one that gets 10 MPG on a good day and is a slug) but it is an economical alternative to a Durasmack for towing and pure torque even at today’s fuel prices.

 

This fall when the ULSF diesel hits the pumps and diesel prices spike while costly fuel additives are needed for pre-2007 diesels there will be a lot of Durasmack, Powerjoke and Cummins trucks coming up for sale so I predict big block gas hogs could become popular again….just in time for GM Powertrain to discontinue the 8.1 at the end of 2007 MY for the new truck buyers. Way to go GM....good way to sucker people that need tow rigs into only having access to $3000 more expensive diesel trucks than a 2006 model rigs....then again..maybe it is not GM's fauld but our own government.

 

After all this Talk…..If I were you…I would sell the 8.1 and part out the donor truck to the steet rodder’s and off-roader’s and stick with what you have or trade it in on a 8.1L truck.

 

If your are still crazy enough to proceed. PM me and I can help you through your maddess.

Haulin' 8.1 Enthusiast

Haulin' 8.1

Posted
Posted

I'm glad Larry's here because he feels like talking too. As he mentioned there's a lot that needs to be said in a serious discussion over this and he seems willing. I'm not but I will offer small points when I feel it will help. I think Supercop isn't trying to be offensive, he just gets shocked when he sees a truck guy who can type. LOL

 

First, I do know that the front frame section for the 8.1/DM is unique to them and you should compair the two closely to make sure you will be able to fit the engine into the truck with just a mount swap. It may not be that easy. Also the radiator core support is unique. The bolt holes you need may be in the wrong spots on a 6.0 truck. The core supports are usually on Ebay for cheap enough but the frame sections aren't. You may find the need for custom mounts and the LS engines use completely different mounts. The 8.1 still retains BBC style mounting pads. There are crossmember kits to swap BBC into LS-1 equiped cars so that might be a way to compair differences if you can look at them close enough.

 

Second you should replace the crankshaft sensor (going into bell housing behind left-hand cylinder head) on the donor engine. All '01's got the early one that's crap. Scan the forum for evidence that it will go out soon. Other than checking the power steering pump pulley for alignment that should do it. My '01 8.1 is trouble free (with preventative maintainence, and very fast.

 

I don't know what's up with Larry's but once the alli grabs passing gear the race is won. True the 6.0 might grab passing gear faster because it's only one down and not two but they don't get anywhere in .5 second. From a dead stop, forget about it. 8.1 rules. I've yet to have a diesel of any make smoke me, and several have tried. I don't know their specifics but they started it. My truck has been faster 3/4 times and even with the others. Nobody has left me. I do realize there are faster diesels out there (they've raced my cars pretty well) but none have found my truck yet.

 

I've got Ranch Hand Bumpers also, I didn't realize that this was a Texas marker but since it is where are you located?

 

Great, now I've talked too much and I'm running late.

 

Vernon

mrfishaholic Enthusiast

mrfishaholic

Posted
  • Author
Posted

Yes, I am in Texas, Austin area. Thanks for the insight to the motor and radiator mounts, will look at that....and the crankshaft sensor, that too, great points, things that I am truely looking to know so I can do it all at once.

linda Enthusiast

linda

Posted
Posted
as the 6.0 is actually faster and more athletic around town.  If yanking trailers and the braging rights of having big pissers under the hood is your deal then the 8.1L is for you.  Believe me….the 8.1L is NOT fast (I own one that gets 10 MPG on a good day and is a slug) but it is an economical alternative to a Durasmack for towing and pure torque even at today’s fuel prices. 

 

 

I will have to whole heartedly disagree... :fume:. Even before i installed the blower, this truck was very quick. Kept its own with many a car, and no unmodified DMax or 6.0L HD truck could even come close in the first 1000'. The 8.1L does however leave a little to be desired on the top end, it redlines at about 5100rpm. Personally, if i was in the situation you are right now, i would probably build up the 6.0L. Throw in a mild cam, yank converter, some low comp forged pistons, maybe a set of heads and a turbo/supercharger and be set. All this would probably be easier than a complete 6.0L -> 8.1L swap. Remember, a front suspention overhual will be needed as well, these RAT motors are heavy suckers.....not as much aluminum as the small blocks ;). If its just the knowing that you got a torque monster under the hood and you got the time and resources to do it, i say go for it! Nothing like the growl of a 496 under the hood.. :confused:.

 

My '01 8.1 is trouble free (with preventative maintainence, and very fast.

 

I don't know what's up with Larry's but once the alli grabs passing gear the race is won. True the 6.0 might grab passing gear faster because it's only one down and not two but they don't get anywhere in .5 second. From a dead stop, forget about it. 8.1 rules. I've yet to have a diesel of any make smoke me, and several have tried. I don't know their specifics but they started it. My truck has been faster 3/4 times and even with the others. Nobody has left me. I do realize there are faster diesels out there (they've raced my cars pretty well) but none have found my truck yet.

 

I agree.

 

 

EDIT: I see now you have changed your mind...to bad, i was looking forward to following this one.

mmmikkke Senior Enthusiast

mmmikkke

Posted
Posted
as the 6.0 is actually faster and more athletic around town...

I think what Larry's referring to is the extra weight of both the engine and the trans. Trans is 100 pounds heavier and I think the engine's about 300 pounds heavier. So where a 6.0L/4L80E RCLB might have pretty close to 50/50 weight distribution front to back, an 8.1L/Ally RCLB will have somethign closer to 55/45. That leads to less nimble handling, and it makes the truck plow on turns, and it doesn't "feel" like an extension of the driver.

 

Don't get me wrong, I actually wish I'd have had the b**ls to get an 8.1 back in '05 when I bought my truck...but there are a few advantages to the 6.0L and this is one of them.

Larry Enthusiast

Larry

Posted
Posted

You kinda got it, the 8.1L backed by a 6 speed manual is a slug around town at 5000 ft elevation where I live….and I am quick and stirring gears. The 6.0L with a 4L80E is quicker from stoplight to stoplight and much more sprintiful. (sprintiful) Is that even a word?

 

BUT, the 6.0L can’t pull a greasy string out of a Coke bottle at this attitude compared to an 8.1L. That is where the 8.1L shines…..towing.

 

Like I said before….the 8.1L is an economical alternative for towing next to a Durasmack.

 

Now, at 700 ft elevation in Detroit even a 2.4L HHR LT feels like it has some gonads.

  • 4 weeks later...
5Alive Enthusiast

5Alive

Posted
Posted

I was intrigued about what Larry said regarding the 6.0 being more athletic and spirited (assuming empty, no tow, no load) than the 8.1.

 

I was curious if the same rear axle ratios were involved in this comparison? (ie... a 6.0/4.10 might feel faster than an 8.1/3.73 ?)

Haulin' 8.1 Enthusiast

Haulin' 8.1

Posted
Posted

He means in the way it responds to steering and holds the curves. Not in how it feels WOT in a strait line. The same truck with less wieght will hold the road better, stop faster etc. I drive a lot of trucks doing my job and get them running as well as possible. Not many trucks feel as fast as mine, but yeah I have to plow through turns and give myself plenty of room to stop.

 

Vernon

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