Project Z06: Oh, Yeah, We’re Swapping an LS3 Into Our C5 Corvette Z06

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Update by J.G. Pasterjak to the Chevrolet Corvette Z06 project car
Mar 12, 2020

After a couple of recent updates, we realized that we were getting a few questions regarding the 530-horsepower, LS3-based crate motor we were prepping for a dry sump install. Then we realized that we never really directly addressed the fact that we were replacing our 2004 Corvette Z06’s original, 100,000-mile LS6 with an LS3-based powerplant. 

So, yeah, we’re doing that.  This video does a pretty good job of explaining what we’re installing and why, but in case you’re trapped at work and can’t watch it, here’s the elevator speech:

Our new engine of choice is an LS3-based, 6.2-liter crate motor from BluePrint Engines, sourced through Summit Racing

Our decision to repower rather than rebuild was a tricky one, but ultimately we made the decision for a few reasons. First, they’re not making LS6s anymore. Although it was a great engine, at 405 horsepower, it was fairly capped out on performance at the factory rating. 

Bolt-ons and tuning could net a few more ponies but making serious power–modern Corvette or muscle car power–meant replacing hard parts like heads and cams and bottom end stuff. 

Heads and cams can be done without a complete rebuild, but with 100,000 miles on the clock, was that a risk we really wanted to take? 

And as we started pricing out a complete rebuild, the numbers were coming shockingly close to the cost of just updating the entire powerplant with more modern hardware. Plus, when we were done with that hypothetical rebuild, we’d still have an older-design engine.

At this point in time, it almost seems like a tossup, to be honest: Rebuild or replace seems like six of one or a half dozen of the other. 

But five years from now, rebuilding will likely be even less of an option as the supply of good used LS6s dries up even more, and more modern crate engines continue to flood the marketplace.

So we opted for a 530-horsepower, plug-and-play crate engine. Interestingly enough, the friend who bought our old LS6 is rebuilding it and will be installing it in a C5 as well. Our project power numbers–and budget sheets–are looking very similar. It will be interesting to compare the final tally of both when we’re both finished. 

But plug-and-play isn’t always as seamless as it sounds and replacing an older LS with a new one creates some challengers. There are a few workarounds we have to deal with, and we’ll be detailing those as the install progresses.

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Comments
AngryCorvair
AngryCorvair GRM+ Memberand MegaDork
3/12/20 3:33 p.m.

I can haz ur LS6?  It will end up in MonZora, I promise.

David S. Wallens
David S. Wallens Editorial Director
3/12/20 3:38 p.m.
AngryCorvair said:

I can haz ur LS6?  It will end up in MonZora, I promise.

"Interestingly enough, the friend who bought our old LS6 is rebuilding it and will be installing it in a C5 as well." smiley

poopshovel again
poopshovel again MegaDork
3/12/20 3:56 p.m.
AngryCorvair said:

I can haz ur LS6?  

Came here to say diss.

David S. Wallens
David S. Wallens Editorial Director
3/12/20 3:58 p.m.

In reply to poopshovel again :

Sure. I'll send over a Paypal invoice. 

dean1484
dean1484 GRM+ Memberand MegaDork
3/12/20 4:59 p.m.

I am going a bit off the rails here but what made you stop at 530 hp?   

Best Hp/$$?  

Other parts of the car would need upgrading and again $$$$ becomes an issue?

More HP and speed does not always mean more fun. Is the 530 mark the sweet spot for the C5 platform?

At some point the cars ability exceeds the drives ability.  This is hard for some to accept.  There is no point in building a faster better car if the driver does not have the talent to use it.  Is this a case of this?

You don't want it to be faster?  I have had cars that I could make faster but I did not want them faster.  So ya this is a thing that I completely understand.

Would more HP detract from what made you like the car in the first place?  At some point a car with increase capabilities becomes a different car. Sometimes that is not a good thing.  

Leaving room for future modes and GRM content?

 

 

BoostedBrandon
BoostedBrandon SuperDork
3/12/20 5:14 p.m.

The LS6 has been installed and is running, it's just waiting on a tune.

And no, it's not mine, unfortunately.

stuart in mn
stuart in mn MegaDork
3/12/20 6:24 p.m.
dean1484 said:

I am going a bit off the rails here but what made you stop at 530 hp?   

 

My guess is because with one click on the Summit website, you have a plug and play 530hp engine, with good street driving manners and a warrantee, on its way to your doorstep.

 

AngryCorvair
AngryCorvair GRM+ Memberand MegaDork
3/12/20 6:38 p.m.
David S. Wallens said:
AngryCorvair said:

I can haz ur LS6?  It will end up in MonZora, I promise.

"Interestingly enough, the friend who bought our old LS6 is rebuilding it and will be installing it in a C5 as well." smiley

Uhhhhhhh, words... words... more words... reading sucks!  

docwyte
docwyte UberDork
3/13/20 10:35 a.m.

Just doing a cam swap on the LS6 will net huge gains.  On my old LS1 with the "crappy" 243 heads I made +50rwhp by installing a baby cam.  A much larger cam would've given me even more power.  The LS6 heads you already have are far better than the 243's I was running, so I don't really understand your $$ argument here. 

Toss in a cam, pushrods and valve spring upgrade and run it.  If it blows up, replace it with an LS3.

TurboTodd
TurboTodd New Reader
12/20/20 9:16 a.m.

Why not an LS7?  Sure more money.  I could see"Too much torque for an autox car", but this is a track car with cage.

Dork joke:  LS6++ = LS7, obviously

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