So my ls1 had a failed lifter and all the needles went through my engine and the main and rod bearings are destroyed. The crank actually doesn't look that bad but I know I at least need to have it turned. I am going to get a quote on align honing the mains, putting in new cam bearings, turning the crank, honing the cylinder walls and cleaning up the block but if that price is to high then I am going to be looking for a LQ4 truck engine and use my ls6 intake with a port and polished TB, stock 243 heads and a custom grind cam.

Now I've seen ls6 engines cam only make roughly 430rwhp. And then when I get on here and see people building there lq4s with a cam, 243s and ls6 intake they're hoping to barley break 400rwhp. Now I would assume the extra cubic inches would actually net more hp not less. Now what's the deal or am I just misinformed?

And what are you guys estimating from this setup? cam will be in the 235/243 .61x-.62x range give or take a little.

 

What will the compression be?

 

if I acquire a lq4 I will leave the stock pistons in it and I am pretty sure with the stock 243 combustion chamber it will bring right under 10.5:1

someone correct me if I'm wrong

 

exhaust setup will be pacesetter lts (yeah yeah I know) and tsp true duals

 

In theory if everything else is exactly the same a LQ4 should see the same power as a LS6, and actually have a slightly better torque curve

 

Why a better torque curve? If everything is exactly the same (cam, heads, pistons, everything) wouldn't the torque curves match up perfectly? At that point the only difference is the iron block.

OP, a LQ4 with 243 heads and that cam will be a very fun engine. You might want to consider the 0.41" MLS head gaskets for tighter quench. That will bring your compression up to 10.9, which will help that cam run even better.

 

The extra cubic inches from a 6.0 compared to a 5.7 will cause the the torque to peak a little earlier. Nothing huge but it is there

 

I'm an idiot. I read "LS6", but I thought "LS2", so I was REALLY asking why would there be a difference between LQ4 and LS2 if all was equal.

Now if only there was a smiley for Chris Farley banging on his head saying "So! Stupid!"

 

Haha no problem, I've done that before too

 

So what do you guys think I'm looking at power wise? I'm just trying to determine which route I should take and I was confused that a bigger cubic engine would make less power

 

420-450, depending on the dyno and the tuner on the stock 243's. If you work the heads over a bit, you could get as high as 470.

 

There isn't a huge difference in cubic inches and it gets offset by the low compression lq4 pistons...unless you do something to bump compression to equal the ls1/ls6 it will make less horse power. I also think 430rwhp is optimistic for a ls6 unless it's a large cam. 420 is more reasonable.

I just swapped from ls1 to ls2 with nearly identical cam profiles, and even with porting the heads I gained 30hp and 30ftlbs peaks. The primary gain from the ls2 is the broader torque curve which makes a fun street car.

An lq4 is also going to add just over 100lbs to the nose of the car. This is worth considering if you do a lot of serious drag racing, autox, or just like a better handling car. I won't put an iron engine back in my car unless it's a stroker or I have no choice.

If the ls1 is salvageable and you do not intend to put different internals in the 6.0l I would rebuild what you have.


FYI, my dyno thread is in the dyno section. It made 418rwhp unlocked (~445 locked) with ported 799s which are the same as 243s. This is with heads milled .013" and flat top ls2 pistons...the dished lq4 piston will drop compression over what I have by a decent bit.

 

Yeah I'm taking the crank and one rod to the machine shop just for them to tell me if it can be saved and then I have to worry about the block. If it's cheaper to machine everything then I would rather keep my aluminum block

 

Thanks for the reply everyone! Keep the hp guesses coming! Lol