My C5 LS3 Build

[C5Natie]

Hey guys. Havent been on here for a while but thought I would share my current LS3 build with you guys. Back in May I lost a couple main bearings in my LS6 to a damaged lifter and a eatened up cam lobe. Instead of tearing through the block again, I rebuilt it 3yrs ago, I decided to upgrade. Thing is I was on a budget so I decided to go with a LS3 build since parts are cheap and these motors are beast with little mods.

I was able to land a super low mileage L92 short block, which identical to a 6.2L LS3 (same block casting and internals with the exception that the pistons have 2cc valve reliefs). I then got hold of a new LS3 top end, new intake from a friend and new heads from GMPP. A Ligenfelter converter box should allow me to run the LS3 without swapping the cam sensors and crank reluctor wheel.

Here's a list of whats going into this motor so far:
GMPP LS3 heads
LS3 intake w/90mm throttle body
PRC .675 valve springs
Stock rockers
L92 block, DOD delete
Ported and shimmed GM LS6 oil pump
TSP 231/236 .641"/.615" 114lsa cam
TSP 1 3/4 headers
Short x-pipe with two Dynomax bullet mufflers dumping under car
3600 SS Yank
Built 4L65E w/3.42's
LPE 24x58 tooth converter box

Getting things started
663

Clean internals, low mileage
664

Cam and new oil pump are in
665

[C5Natie]

LS3 heads, huge intake valves!
666

2.165" yet only 87 grams
667

Installing the PRC .675 valves
668

What it'll look like in a few days
669

[Damian]

You can store that old LS6 in my Typhoon if you want. I won't charge you storage fees or anything.

[heypal]

Oh Gawd a build thread as if the text messages weren't enough to make me feel slow and poor.

[C5Natie]

You can store that old LS6 in my Typhoon if you want. I won't charge you storage fees or anything.

Lol. I have a friend who said he would take but if he doesnt it will be on the market. It has Probe forged pistons and rods with full ARP 2000 bottom end hardware. That would be pretty cool in a Typhoon.

[C5Natie]

Oh Gawd a build thread as if the text messages weren't enough to make me feel slow and poor.

C'mon, I only sent you like two pictures. At least your car runs right now..if you fixed that steering rack.

[blackax]

C'mon, I only sent you like two pictures. At least your car runs right now..if you fixed that steering rack.

Ya no...his bearings are gone and the motor is out of the truck.

If the price is right i might be down to get it (need an LS for my impulse)

[Shaolin Crane]

I'd like an ls6 plz. Maka mustang moe bettah

[Damian]

Lol. I have a friend who said he would take but if he doesnt it will be on the market. It has Probe forged pistons and rods with full ARP 2000 bottom end hardware. That would be pretty cool in a Typhoon.

Let me know so I can put it on layaway.


Can the LS3 be better power wise than the LS6? Isn't the LS6 505hp stock compared to 420hp?

[Shaolin Crane]

Ls6 is a stronger ls1 basically

[Damian]

LS6 or LS3? I know the LS1 is stronger than the LS2.

[Shaolin Crane]

Uhm what? The ls6 is a stronger block then the ls1, same displacement. Different valve springs to put it simply. The ls2 has more displacement then the ls1

[SeanPlunk]

Uhm what? The ls6 is a stronger block then the ls1, same displacement. Different valve springs to put it simply. The ls2 has more displacement then the ls1

Different heads too.

In order:
LS7>LS3>LS6>LS2>LS1

The LS6/LS2 could be debated, but I prefer the LS6 despite the lower displacement.

[Shaolin Crane]

Different heads too.

In order:
LS7>LS3>LS6>LS2>LS1

The LS6/LS2 could be debated, but I prefer the LS6 despite the lower displacement.

Head castings are the same, valves and valve springs are different.

[fiveohwblow]

I'd like an ls6 plz. Maka mustang moe bettah

GFY

[Shaolin Crane]

GFY

Sorry, this be my home.

[fiveohwblow]

Sorry, this be my home.

Meh

[SeanPlunk]

Head castings are the same, valves and valve springs are different.

I don't think that's correct.

[Shaolin Crane]

I'm going by my builder, he said they have different valve train hardware but the castings were the same.

[blackax]

I don't think that's correct.

LS6 heads are the same as the LS2 heads. (springs do differ)

You can use LS3 heads on a LS2 block but not on a LS1/LS6 block (This is mainly do to bore size LS1/LS6 = 3.898 LS2 = 4.000 LS3/LS9/LSA = 4.060 LS7 = 4.125 )

LS6's are better for and NA application

LS2's are better for FI application (it gets called the truck motor because of the gm LQ9)

[blackax]

And from what I understand is that the LS3 Heads flow better then the LS7 heads on the low end but die out on the top

[blackax]

From wikipedia about the ls2

It is similar to the high-performance LS6, but with improved torque throughout the rpm range. The LS2 uses the "243" casting heads used on the LS6 (although without the sodium filled valves), a smaller camshaft, and an additional 18 cubic inches. The compression of the LS2 was also raised to 10.9:1 compared to the LS1s 10.25:1 and the LS6s 10.5:1

[C5Natie]

And from what I understand is that the LS3 Heads flow better then the LS7 heads on the low end but die out on the top

Ls3 heads flow great up top with the right cam. If anything port velocity can suffer when the heads get ported too much, losing a bit of torque on the bottom end. It depends on cam selection but Ive seen LS3's make great power up to 6800rpm or higher. The intake ports and valves are so big that you dont need as much duration on the intake side and the right cam can maximize the exhaust velocity.

I think the 6.2L motors are fast becoming the best bang for the buck project motors. A brand new set of GMPP LS3 heads cost me $640 for the pair, new and complete. Also, so many trucks/suvs and cars have the 6.2L that theyre getting easier to find.

[C5Natie]

I think the C6 LS3 revs up to 6600 but the stock valve springs suck luckily they can get away with a smaller cam due to how good those big valves flow. Maybe thats why some may say they "die up top" vs an LS7, being stock that is.

[blackax]

Ls3 heads flow great up top with the right cam. If anything port velocity can suffer when the heads get ported too much, losing a bit of torque on the bottom end. It depends on cam selection but Ive seen LS3's make great power up to 6800rpm or higher. The intake ports and valves are so big that you dont need as much duration on the intake side and the right cam can maximize the exhaust velocity.

I think the 6.2L motors are fast becoming the best bang for the buck project motors. A brand new set of GMPP LS3 heads cost me $640 for the pair, new and complete. Also, so many trucks/suvs and cars have the 6.2L that theyre getting easier to find.

I agree on the power the stock heads can make with the LS3 I was just comparing them to the LS7 head.

I'm a fan of all the gen IV small blocks (ls2,ls3,ls7) I love my LS2 and the truck blocks are so nice for huge boost numbers (cant beat iron blocks in huge Fi numbers)

[C5Natie]

Yeah, theyre very similar heads. LS7 intake valves are 2.20" vs the LS3 2.165" and theyre cc is for a 4.10" bore minimum so theyre gonna flow a bit more up top. Thats why they got crazy top end. But now even regular LS3 Vettes are hitting 180mph+ stock. Crazy. We are now in the golden age of performance, muscle cars cant touch this technology.

[C5Natie]

Heres a thread with a guy, screen name Burrhos, making 517rwhp/462rwtq with cam only bolt on LS3 C6, n/a. Ran 10.67@129mph. See post #8.

http://ls1tech.com/forums/generation-iv-internal-engine/1566217-people-running-ls3-dyno-et-numbers-wanted-please.html

[Ryridesmotox]

Isn't the LS6 505hp stock compared to 420hp?

405hp in the z06. Other applications like the CTS-v and the GTO have other outputs I think. Just figured I would answer your question. And the sodium filled valves thing is actually pretty sweet. Apparently it allows the valves to remain cooler or something like that.

I agree with you Natie, this is the golden age of performance. You cant find a muslce car that will get over 400hp and still get almost 30mpg like a vette. The technology is amazing now. My cobalt motor internals can handle 500whp from the factory. The LS blocks are total beasts, and the OHV pushrod design is tried and true, and I don't think its reliability and power can really be questioned.

[C5Natie]

Well, I got a lot done this past weekend starting thursday. Got the motor in and assembled it. Turned it over to prime the oiling system and connected the converter box. Should start it up today and button up the car. I'll post some pics of what Ive been up to. Looking forward to getting video of start up, if it starts, and idle, if it stays idling. Lol

Thanks to my friends Carlos, Adrian and my uncle William for lending a hand this weekend. And NO-Xplode for giving me the energy.

[C5Natie]

Made the notch for the bracket to fit. Not pretty but it worked.
http://i1164.photobucket.com/albums/q580/C5natie/IMAG0622.jpg

http://i1164.photobucket.com/albums/q580/C5natie/IMAG0624.jpg

[C5Natie]

Headers got a new coat of high heat ceramic paint. Rustoleum 2000, great stuff.

http://i1164.photobucket.com/albums/q580/C5natie/headers.jpg

[C5Natie]

STEP 1 of install is complete, the block is in. Wasnt the easiest job to line it up with the torque tube shaft.

http://i1164.photobucket.com/albums/q580/C5natie/IMAG0626.jpg

http://i1164.photobucket.com/albums/q580/C5natie/IMAG0627.jpg

[C5Natie]

Motor is basically complete. Cranked it to prime the oiling system. Rotated smoothly, so far so good. All thats left is installing the cooling and power steering systems.

http://i1164.photobucket.com/albums/q580/C5natie/IMAG0633.jpg

[C5Natie]

I had a couple people ask me what my custom exhaust setup looked like, so here is a picture. It weighs A LOT less then a complete xpipe with traditional mufflers. These are NOT cherry bombs. Its a moddified TSP xpipe with a pair of Dynomax 3in bullet mufflers and turn downs. The placement of the mufflers isnt the best for low speed exhaust scavenging but I put this together for wot performance. I gained .3 and 3mph at the drag strip with this setup. Oh yeah...its loud.

http://i1164.photobucket.com/albums/q580/C5natie/IMAG0635.jpg

[Shaolin Crane]

Wait, so you cranked the engine to prime the oil rather then priming the pump? Yikes.

[Vettezuki]

http://i1164.photobucket.com/albums/q580/C5natie/IMAG0633.jpg

:thumbs_up:

[C5Natie]

Wait, so you cranked the engine to prime the oil rather then priming the pump? Yikes.

Turned the starter basically, plugs out and fuel pump disconnected. You turn the motor till oil gets too the heads.

[Shaolin Crane]

Turned the starter basically, plugs out and fuel pump disconnected. You turn the motor till oil gets too the heads.

Yeah, thats not good to do. You want to prime the oil pump. Cranking the engine to prime the oil isnt safe. Engine oil is needed the most on start up, so you might as well be cranking with no oil in it at all. Just for future reference.

[C5Natie]

Yeah, thats not good to do. You want to prime the oil pump. Cranking the engine to prime the oil isnt safe. Engine oil is needed the most on start up, so you might as well be cranking with no oil in it at all. Just for future reference.

There is already assembly lube all over the rotating assembly and valvetrain. This seems to be the common practice for these motors. The block always had oil in it until the end when installed the oil pan so it wasnt ever completely dry. The crank wont get damaged with no load.

[C5Natie]

Oil pump was packed with vaseline too to help with suction on first startup and also act as lube.

[Shaolin Crane]

I've never seen a builder prime an engine by cranking it.

[C5Natie]

LS3 C5, Big Cam Startup - YouTube

[blackax]

I've never seen a builder prime an engine by cranking it.

I hear it all the time with LS motors

[blackax]

LS3 C5, Big Cam Startup - YouTube (http://www.youtube.com/watch?v=xrWDOgGnDWw&feature=plcp)

Very very sexy. How does she drive? Was it an easy swap?

[C5Natie]

Very very sexy. How does she drive? Was it an easy swap?

Thanks! It seems the current tune is very very close to this setup so it actually drives really well. Crazy instant torque. I barely tap the throttle and it wants to go. I know I need a few fueling/timing adjustments but Im in the ballpark.

The swap was much easier then I imagined. I had a friend who is a tech help me pull it out but once I saw how it went, the install was easy. This thing was installed and fully assembled in 2 days. Made me a lot less scared to dive into the motor for any future issues.

[C5Natie]

I hope to get some time on the dyno this month but I ran the car with a tuning wideband on today to see where its at. The existing tune from my old setup is very close. Cruising afr's are great, car idles awesome and pulls plenty of vacuum. WOT afr is at 12.5, when the car kicks down, 4th to 2nd, it goes to 12.2 and immediately picks up to 12.5. No knock. Gonna try to get some driving video soon.

[C5Natie]

Here a vid when I was checking the afr on the 4th to 2nd kickdown. A bit choppy, sorry.

http://i1164.photobucket.com/albums/q580/C5natie/VIDEO0097.mp4

[C5Natie]

Just a little update, going to WesTech Performance this Friday to put her on the dyno. They do a lot of engine and chasis dynoing for all the big performance magazines. Also installed an AEM UEGO wideband last week. Great gauge so far.

http://i1164.photobucket.com/albums/q580/C5natie/IMAG0687.jpg