I know anything is possible with the right amount of money. But I was just curious if a 8.1l with the allison transmission is possible to put into a 2004 1/2ton extra cab sivlerado? How come no one has done one of these? Is the 6.0l a better route? Also is the 6.0l that comes in the GM vans the same as the lq4 or are the intake manifolds different? Thanks for the info guys!

 

I think it would be cool as hell but impractical... why not a 6.0 there a ton more performance parts out there for the small blocks and much easier swap since you accessories and all will bolt up...

 

I think the 6l is better bang for the buck. I wanted to do the 8.1, but heard its a PITA cause you have to change so mutch. With a 6l, you pull one out, and put the new one in.

 

The 8.1 is rated at 340 hp. The truck cylinder heads wont allow for much more power.
GMPP(GM Performance Parts) offers an 8.1L crate engine called the "Vortec HP3 8100-High Tech". It is rated at 525+hp@5200 rpm and 560+lb/ft of torque @ 4000 rpm. 9.1:1 compression, cast iron block, 4.25"x4.37"
It comes complete with:coil, intake, K&N air filter, engine cover,plugs, oil pan.

The book says that this engine has cast iron PORTED cylinder heads, to get the 525+hp rating.

GM made a concept truck called the "Coolside 2" 1/2 ton. It had an 8.1L The iron big-block 16-valve V8 engine develops 575 horsepower at 5700 rpm and 605 lb-ft of torque at 4500 rpm. GM-built parts on this engine include the cylinder block assembly, the cast crankshaft with bearing journals nitrided, the rear main seal and aluminum Gen V/Gen VI cylinder heads, which are not stock for the 8100.
These heads are from the ZZ502/502hp crate engine
Cam is a 230/242 duration at 0.050" of lift, .540/.628" lift with a 112LSA.
4l80E trans and an AWD unit.
It weighs 4600 lbs(est.) and has 14"x1.4" vented rotors that are cross-drilled and slotted and has 295/45zr18 tires on 18x10" rims.
This is 1 pretty wicked pickup truck.

http://www.pickuptruck.com/html/auto.../coolside.html
Anyways, I have been told that the framerails in the front of the HD trucks where the 8.1 and Duramx sits is different than the frames of the 1500 series trucks. Any 8.1 1500 series trucks I have seen have had the front frame section grafted into the 1/2 ton truck.

The Allison is a pretty ineffecient transmission, with upwards of 29-31% total drivetrain loss(includes Allison trans, and the 11.5" 14 bolt rear dif, as well as the heavier U-joints). I would favour a 4l80e/85e trans instead, but I guess if the 8.1 is going to be modified at all, one can sacrifice a few extra lb/ft and hp in the quest for strength and reliability. A full Level 5 Allison that is "rated" at 1000/1000 hp/tqu costs $5200, a level 5 80e from FLT can be had for $2000 less.

A 6.0 would be an easier swap of course as installing 1 in a 4.8, 5.3 truck is as simple as R&R'ing the engine and flashing the PCM.
A VHO (RPO B4V) or a Vortec MAxx truck would be a nice candidate for a boosted 6.0 or an 8.1 inplant because it allready has the 14 bolt 9.5" ring gear rear dif. That rear will take a bigblock 2wd truck "RELIABLY" into the high 11's, the 14 bolt G80 should be tossed whenever it fails, and if serious, aftermarket axles should be used with a Detroit Locker or equivalent.

Another option that sticks out in my mind would be to get a hold of an LS7 or similar engine(forged crank, rods and pistons ideally).Bolton a built 4l80e/85e, Denny's Nitrous Ready Driveshaft and u-joints, 14 bolt rear dif with aftermarket axles and Detroit Locker, some sort of spring wrap controlling device with some sticky tires. This combo would be a nice reliable combo, that would be sure to burn a lot of gas, and put a smile on your face everytime you mash the happy pedal. If you opted for the forged internals, you could sprinkle big cube smallblock with boost or nitrous as you deem necessary.

With large displacement small blocks being easily attainable, and the way that they simply bolt in place of a 4.8, 5.3 or 6.0. Swapping in an 8.1 uses up some money on packaging problems that could be used for performance on the big inch small block.

The big block will always be special, and will instil fear esp.when you roll into the local cruise spot, with the nasty cam loping and the 7.0, 7.4, 8.1L emblems shaking on the cowl hood.

peace
Hog

 

dammit Hog.. you always take the guess work out... you da man...

 

What about a LS2 swap, are they the same as the LQ4/LQ9 ? They seem to put out good power. But how would the LS2 perform in a truck. Would you be able to two with that engine? Which tranny would you use? Also what about the new vortec max? Is it the same as the other 6.0's? I wish they would have had that option when I bought my trcuk!!!!!