# LS1 or LS7?



## 04 GTO Judge (Nov 1, 2021)

Hey guys so probably a dumb question here but is there an easy way to tell an LS1 from an LS7?
I'm asking because when I purchased my car, I was told it had a stroked LS1 in it. However, when I talked to 21st Century Muscle Cars who installed everything, they said it had the Lingenfelter 530HP package with some upgrades to get to 550HP. When I checked the LPE site, this is what it says is in the package:

530 BHP / 530 lbs-ft of torque

Package includes:

Engine removal, inspection and disassembly
Custom LS7 aluminum block preparation
JE 2618 alloy forged aluminum pistons
Callies 4.000" stroke forged steel crankshaft
Manley Pro-Series lightweight I beam connecting rods
Total Seal file fit rings, heavy duty rod & main bearings
Head gaskets & head bolts
Computer balanced rotating assembly
Lingenfelter CNC porting and polishing of LS2 cylinder heads
2.055" / 1.57" one piece stainless steel intake & exhaust valves
Lingenfelter double valve springs, titanium retainers, 10 degree locks & valve stem seals
Three angle valve job, checking of spring tensions and heights
Lingenfelter designed Competition Cams hydraulic roller camshaft
High volume oil pump assembly
90mm composite intake manifold
Properly sized fuel injectors
Lingenfelter High Flow Air Intake
Reassembly and blueprinting of the engine
Professional installation, testing and tuning
Stainless steel exhaust by Corsa Performance - sport system
ATI underdrive harmonic balancer
Chassis dyno testing after installation
Excellent drivability, highway mileage not adversely affected

So I'm just curious if there is a way to tell for sure. I had heard the LS7 has rectangular ports, but I'm not an expert on these motors and that may be wrong.

Here are some engine photos I have if it helps. Thanks for any help!


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## armyadarkness (Dec 7, 2020)

As I mentioned earlier, it's a beautiful car! But where's the valley pan? 

I think its awesome that this forum openly welcomes the new generation GTO owners in, and respectfully treats them as legitimate GTO owners, but the harsh reality is that there's nothing at all on those cars, shy of the badging, which even remotely resembles anything from 1975 back. 

You might get answers to Chevy Engine questions here, but it'll take much longer. To compound the issue, your car has been modified so even the new gen experts are going to be guessing. I mention this because if you don't get many or timely answers, this is the reason. No one here will blame you for going to an LS site to get the facts... but this is the place where evryone will appreciate your GTO.

Im a big fan of the new gen GTO's and I hope to have one some day. Yours is the coolest that Ive seen so far. One of my best buddies just bought one last week, and the first thing I did was to send him a pic of yours.


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## 04 GTO Judge (Nov 1, 2021)

Thanks very much for the reply and kind words! I admit openly that the old school GTO's are way more popular and the first thing people think of when they hear "GTO". Many people have already asked me what this car is. Lol.

I appreciate the info. I did some research and it seems there are some stamp locations for the heads and motor so I'll have to check into it when I have some time. I'm not in a rush...the car is just in the garage except for weekend drives...so it is really just a curiosity of mine.

Thank you for letting me know about the forum and again thanks for the compliments! I'm enjoying the car so far. I'd like to have an old school GTO, but this is what I could get on my budget so that's why I purchased it.


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## armyadarkness (Dec 7, 2020)

Your ride is a GTO to be proud of, just don't ask me where the valves are.


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## RealtoReal05GTO (Dec 5, 2021)

armyadarkness said:


> As I mentioned earlier, it's a beautiful car! But where's the valley pan?
> 
> I think its awesome that this forum openly welcomes the new generation GTO owners in, and respectfully treats them as legitimate GTO owners, but the harsh reality is that there's nothing at all on those cars, shy of the badging, which even remotely resembles anything from 1975 back.
> 
> ...





armyadarkness said:


> Your ride is a GTO to be proud of, just don't ask me where the valves are.


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## RealtoReal05GTO (Dec 5, 2021)

Hmm didn't mean to walk in on yall conversation but I'm looking for answers on my 05 GTO. Ok my mechanic took apart the whole top of my engine and replaced everything with aftermarket parts, plus my LS2 head's was sent too Texas Speed for some CNC work. Long story short my mechanic said the engine was to much for the transmission and the Dyno was inaccurate. What kind of GM transmission could I buy that holds 500-700hp, something I could plug and play.... thanks. Forever Pontiac..


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## GTO44 (Apr 11, 2016)

RealtoReal05GTO said:


> Hmm didn't mean to walk in on yall conversation but I'm looking for answers on my 05 GTO. Ok my mechanic took apart the whole top of my engine and replaced everything with aftermarket parts, plus my LS2 head's was sent too Texas Speed for some CNC work. Long story short my mechanic said the engine was to much for the transmission and the Dyno was inaccurate. What kind of GM transmission could I buy that holds 500-700hp, something I could plug and play.... thanks. Forever Pontiac..


Is your gto an auto and stick car?

As far as horse power, the common “heads, cam, intake” with supporting bolt-ons is going to net somewhere around 450rwhp. On a very efficient setup you may get up into the 475rwhp range. If you’re going with a HUGE cam which would kill most drive-ability you can eclipse the 500rwhp range.

If you have a manual transmission you’re going to be good for a while. You’ll need a better clutch. But as long as you arent launching at the drag strip the T-56 will last a very long time.

If you have an auto its a crapshoot. The 4L60’s are know for giving the ghost on the 2-3 shift with any type of power over stock. You can get a built 4l60 to handle the power. We just got a stage 5 built 4l60 from our tranny builder that supports 700hp. Funny thing is its more expensive than a stage 2 4L80 that will handle 1,100hp. 4l60’s just arent that strong of a transmission. You’d also want a new converter that will handle the power with a higher stall for the bigger cam.

The other thing to worry about is the driveshaft, axle halfshafts, and axle stubs. Ive broken a couple driveshafts and an axle stub (which trashed the rearend) with stock power… These gto’s are heavy cars and its very easy to break something with the IRS rear end. You’ve got a lot of upgrading to do to handle the power reliably…


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