CitrusTheDragon

Let me start with I have a 2004 Ascender(Trailblazer) with a 5.3 that is leaking. I have done some research and have found many people that have pulled the 5.3 and replaced it with a 6.0. I think it sounds like a great idea but also wanted to make sure I build the best motor I can. I know a lot of LSx parts are interchangeable but what combination would make the best motor for a 6.0 6speed truck.

So far I'm thinking of a LY6 block with stock bore and a 4" stroke, L92 heads,5.3 oil pan, and then from there I have no clue. So suggestion would be helpful.

Next question is how hard would it be to keep the VVT and install a newer gen motor and trans into my truck. Can a keep my existing ecu or do I need the one out of the donor truck?

Lastly please be gentle I'm new to this stuff.

1989GTA

I can tell you that if you want VVT you will have to go to the new ECM such as the E38 or the one out of the donor truck in your case.

Price wise you might be better off just getting a 6.0L motor out of something else that is compatable with what you have. That would be pretty much plug and play.

The conversion is doable but it might nickle and dime you to death in comparison.

CitrusTheDragon

How so? My other idea was LQ9/4 block 4"stroke, L92 heads, L76 intake manifold, 90mm TB, but I still need to figure out what injectors, coils, exhaust manifold to use and then if a supercharger is worth adding to the mix. Also I Have to keep it California street legal.

Adam123

iTrader: (1)

Truck coils are considered better than cars, the ones with fins on the back. 42lb injectors should be large enough if not a little to large. You should also determine where you want your torque to come in. From what I understand the cathedral port heads make better low end torque and the square port heads have better mid-range torque. Then choose the cam to go with the heads. I would think with a heavy truck/suv it would be better to have great low end torque to get the thing moving. I don't know what to tell you on how to keep it California smog legal. (Darn tree huggers)
Think about how you want the engine to behave then call someone to offer you a cam for it or build you a custom one. I seen a thread on here awhile back from Martin @ Tick performance (I think) that announced a new set of truck cams and how they would behave.
Good luck.

CitrusTheDragon

What will need to be modified on my truck to make this work?

BigEd_72455

iTrader: (7)

that's a trick question

its according to what year engine you get, if it has DoD, VVT, or any of that stuff.

Other guys on here know a hell of a lot more on that subject than me.

I stuck with the 5.3LS in a 93 S-10, now I am going carb'd..

CitrusTheDragon

my truck is just really heavy for the 5.3 and to run a 6speed auto I have to go with an LQ9. I read some where if I run a E38(whatever that is) it will work but I don't know if that will be a plug n play or if I'll have to splice wires and run piggyback to make all the acc work.

cam

iTrader: (9)

I'd stick with a gen III 24x 05 or older 6.0L or any other LSx of that vintage. Swapping to a genIV is not set up isnt worth it expecially considering your already plug and play gen III ready to go.

If you do a gen IV swap then swap everything from the same model year as the engine and get all the computers and harness stuff and get info from alldata or by searching for your pinouts and have at it.

The new 6spds are no screamin hell of a trans anyways. 4L80e is a way better choice in terms of power capability, cost, and parts availability etc. Not to mention 10 times easier to install and tune than the 6spd.

CitrusTheDragon

honestly I was just thinking of better MPG, I rarly tow anything but I do drive it everyday. The DoD and VVT sounds awesome but I really am not looking to hack and splice wires to get it to work for me. Or nickel and dime myself to death. I guess if I have to use a 4speed I will but from what I understand I have a 4L60 right now is the 4L80 better on mpg? Are there anyother fuel friendly trans mods or swaps I can do?

cam

iTrader: (9)

six spd auto swap wont make much difference in mileage. 1 or 2 mpg gain TOPS. Same as AFM its worth 1 or 2 and VVT maybe 1. Its allllllllll those little things that add up in complexity, but also increase mileage/performance somewhat, but the gains are small.

If mileage is what your after stick with the 4L60 and drop the rear gear to a 2.73 and leave the stock cam alone in a 4.8L and enjoy 30mpg if you drive at or near speed limits on the hwy.

CitrusTheDragon

The 4.8L get worst milage then the 5.3L in my truck. I have the large 7seater suv