LS1 to 6.0 LQ4

[maxum]

I have been having trouble keeping transmissions in my car. I have lost count of how many we have been through. I keep cracking pumps and input shafts on torque converters. After many hours of engine and transmission work and research we have discovered that the huge amount of front to rear endplay in my crankshaft is the cause of my problems. Long story short, I need to replace the engine. I have a brand new 6.0 L for a 2003 Chevrolet truck sitting in my shop. I am trying to decide if i should put this engine in my car and what type of performance i could expect out of it. I have LS6 stage II heads with a G5xIII cam in my car with the fast intake, headers, true duals etc. The last time i dynoed the car I was putting 458hp to the wheels. I would like to keep similar amounts of power. Is it better to ditch the 6.0 and just buy me another ls1 long block or is it better to build up this 6.0 block. If it is better to keep the 6.0 block, what would I need to do to get similar horsepower as to what I'm getting now? Thanks for any ideas or input.

[Firebirdjones]

Sounds like you lost the thrust bearing.

The 6.0 already have similar casting heads that the LS6 does (317's??) but they have a larger combustion chamber to knock the compression down around 9.5:1

I'd do the 6.0, pull your stage II LS6 heads and stick them on the 6.0 to bring the compression up, along with the G5xIII camshaft and you'll have a stout 6.0 package under the hood that should have more of a broad torque curve and probably make a tad more HP given the larger 4" bore, it should unshroud the valves a bit and allow the heads to breath better.

[maxum]

Thanks for the reply. Thats what I'm leaning towards, I was just wanted someone else's opinion! I was just unsure of what the compression would be with my stage II heads on the 6.0 engine.

[Speed_kills_WS6]

There's no replacement for displacement!!

[Firebirdjones]

Thanks for the reply. Thats what I'm leaning towards, I was just wanted someone else's opinion! I was just unsure of what the compression would be with my stage II heads on the 6.0 engine.

Depends on what the heads were milled to, which changes the size of the combustion chamber.

I know the stock combustion chamber cc for the 243's is around 64cc. They provide a 10.5 compression ratio on the 346. On your 364 it would bump that up a tad higher, but nothing extreme.
Even 11:1 is easily doable with the right camshaft and good tuning. I don't know the specs on your G5xIII camshaft or even who makes it.

[Jay37]

I would go with the 6.0, it's bullet proof.

[02transamce]

+1 6.0 will do fine with the heads and cam in your t/a,good luck.

[garygnu65]

you will need a tune to install the 6.0 ,use the ls6 heads on the 6.0 and pull a little more timing out for the higher compression.sell the used ls1 block .

[Firebirdjones]

I'd tune it anyway, no matter what the combination, changing things around like that.

He may not have to pull timing depending on where he lives, gas available, elevation, and if the camshaft he is running has a fair amount of overlap.

It's pretty easy to get an 11:1 aluminum headed motor to run on pump. I've got cast iron headed motors with that much compression running pump just fine, with the right camshaft and tune.

[bluonblk99]

i have a 6.0 from an 04 silverado with stock ls6 heads and a trickflow cam and it makes about 430 whp with an m6. to me its a great motor with plenty of power and torque. with intake and heads should put you up to or beyond your previous ls1 power and like before mentioned they are bullet proof

[PFM]

The only thing I would worry about is the warranty on the new 6.0 motor. If you put your heads and cam in and she blows up your left holding the bag. Been there and done that already.