An LS3 crate motor costs about $6.5-7k (See here: LS3 Crate engines available from Sam's Performance. - Australian LS1 and Holden Forums). On top of that would be fitment, engineering certificate etc plus any additional parts. Also, i don't know but could you use your LS1 transmission and bolt it up without modification? A cam package would be around 2-3k in parts. So that's about 9-10k in parts, plus all labour. Probably around 15k all up i'd say. Cam and head package and stroker package on your LS1 would be about the same and will probably yield a little more power.
One quesiton, might sound a bit silly... why does stroking your motor give it a rougher idle and more noise? Or doesn't it? The only strokers i've heard have cams so yeah is it the cam that gives it the rough idle? Thanks.
you can get an ls2 fitted and tuned for 7000 so that might even be a better option there still if the ls3 is too much. With a cam you can get 300rwkws easy. Ive seen cars with big cams that make 340+. thats more then a storked ls1 and it will be cheaper and will run better.
In that case, why not just get an LS2 408 short motor from come racing for $7500 (C.O.M.E. Racing Latest News). Cam and head it and will be better than LS2 crate engine with cam, and LS3 transplant which would cost the same.
Why is an ls3 better? better heads then working ls1 heads? What is the ci capacity of the ls3? (I know its 6.2ltr) but what is that in ci.
Does it work out cheaper to go with ls3? maybe Tom SIG-054 could give us an idea of price after swapping the needed parts.
yeh from what i know its mainly the cam that gives it the rough idle, but may also depend on head work etc, if you've got a decent cam but not enough air flowing through or not enough fuel cause of injector size or fuel pump not capable enough then the tune wont be spot on so won't be as smooth, but depends on over all package and tune from what i know.
loudness, will be a bit louder with strocker, but ussualy would have a slightly bigger exhaust id say so would be a bit louder from that again. although 383 in a ls series motor might be a bit smoother than say a 5liter due to the bigger engine size, i could be completely wrong about all of this though so don't quote me on it, as i don't deal with performance cars.
Can get away with it for under 10g if your carefully searching for parts and doing your own research.
Heres some info ive found on the LS3, and why its a better motor over the previous LS engines.
Overview: 2008 Corvette 6.2L V8 (LS3) Engine
Starting with the '08 Corvette, the world was first introduced to GM's latest small block V8 creation – the 6.2-liter LS3. A continuation of the industry leading V8 engines from GM Powertrain, the LS3 kicks out 430 horsepower and 424 lb.-ft. of torque. (In the Corvette, those numbers go to 436 hp and 428 lb.-ft. of torque with the optional dual mode exhaust system.) It's a brute of a small block with 376 ready cubes at your beckon call.
The LS series of engines from GM Powertrain have broken new ground for efficiency and performance from a pushrod platform engine. The LS3 continues the engineering breakthroughs with revised cylinder heads featuring rectangle ports borrowed from the vaunted LS7. The heads feature 63 cc combustion chambers, 2.16-inch intake valves, and 1.59-inch exhaust valves. The camshaft features an aggressive .551-inches of lift on the intake side with less overlap (than the LS2) for even greater airflow and power. Rocker arms with a 1.7:1 ratio sit on top of the heads.
In the bottom end, the aluminum 6-bolts/main block features 4.06-inch bores and 3.62-inch stroke. A nodular iron crankshaft, powdered metal rods, and aluminum pistons (10.7:1 compression ratio) round out a rev-happy short block. Red line for the LS3 comes at 6600 rpm, and you will get there very quickly.
6.2L V8 (LS3) CAR ENGINE
Description of New and Updated Features
Displacement increase to 6.2L from the 6.0L LS2
Performance enhancement from base Corvette LS2
SAE Certified Power & Torque
Horsepower increase from 400 to 430
Torque increase from 400 to 424 lb.ft.
Additional +6 Hp increase with optional active exhaust system
High flow cylinder heads
Higher flow intake manifold with acoustic shell
Larger bore block with structural improvements
Higher flow injectors
Acoustic beauty cover
For 2008, General Motors Powertrain engineers have again added a performance kick to the Corvette base engine with introduction of the new LS3 6.2L engine which replaces the LS2. The 2008 6.2L LS3 V8 with 430 Hp @ 5900 rpm and 424 lb.ft. torque @ 4600 rpm is the most powerful Corvette base engine ever and is SAE Certified for 2008 model year.
The LS3 engineering team focused on design elements to increase flow efficiency in addition to the displacement increase to meet the performance enhancement. The bore was increased to a larger 103.25 mm diameter compared to the LS2 bore of 101.6. Engine stroke remains at 92.0mm. Intake flow efficiency was optimized by straightening out and optimizing the flow path from the intake manifold into the cylinder heads. A high flow efficiency induction system is borrowed from the Z06 application. The cylinder head exhaust ports have been modified to increase flow. Also now available in the Corvette with the LS3 is a butterfly valve in the exhaust system which opens at high exhaust flow levels and by-passes the "tri-flow" S-shaped path the exhaust gases normally follow. This reduces exhaust restriction, yet allows the Corvette LS3 to hum at a more muted burble during part-throttle operation. The LS3 also meets the more stringent Bin4 emission standards and again avoids the gas guzzler tax. The small block tradition of more for less continues.
High Flow Cylinder Heads
The intake port shape size and shape have been modified to increase flow. The higher flow intake ports are similar to the L92 6.2L. Casting changes were made to increase the opening at the exhaust face to improve exhaust port flow. A new exhaust manifold opening is required to match the heads.
The inlet rocker arm is offset 6 mm between the valve tip and rocker bolt/push rod to enable a more direct intake port. The intake valve diameter is increased from 50.8 to 55.0 mm. Hollow stem intake were implemented to enable the 6600 rpm capability (13% reduction in mass from LS2). The 40.4 mm diameter exhaust valves are carried over from L92. Carryover LS2 high load valve springs are also included for 6600 rpm capability. Intake lift increases from 13.25mm to 14.0mm. Exhaust lobes are carryover LS2. Camshaft timing is revised.
Higher flow intake manifold with acoustic shell
Intake ports revised to match new cylinder head. The new composite intake manifold is manufactured with a lost core process to improve runner to runner variation and to reduce flow losses. Acoustic foam is sandwiched between the outside top of the intake manifold and an additional "skull cap" acoustic shell to reduce radiated engine noise. Structural enhancements have been added to the manifold bosses.
Larger bore block with structural improvements
Casting and machining in the bulkheads was revised to improve block structure and to improve bay to bay breathing. The enhanced cylinder block is shared with the the 6.2L truck applications.
A new larger diameter piston design is introduced for which includes design enhancements for the higher engine output.
Higher Flow Injectors
Higher flow 5.0 g/s injectors were used from the LS7 engine.
New Acoustic / Beauty Cover
The new beauty cover has a revised appearance and new acoustic treatment.
Article by Halverson (2007)
From the outside, the LS3 case looks like last year's LS2. If you have sharp eyes, you can see the larger bore, but the other major change is deep inside. Image: GMPT Communications.
Short Block Details
World-class engines have robust blocks, or "cylinder cases," as powertrain engineers say. The '08 Vette's 378-cubic inch, LS3 uses the same block as the L92, a high-performance Vortec 6200 truck engine. But–don't start flaming us about SUV motors. The L92 is light, compact, reliable, durable and powerful–just the foundation a Corvette engine needs.
The LS3 case shares basics most aluminum Gen 3s and 4s have had since that engine family debuted in the 1997 Corvette: deep skirted, 319-T5 aluminum block with siamesed, cast-in-place, gray iron liners which are centrifugally-cast to increase density and allow thinner walls, long head bolts threading deep into its main bearing webs and six-bolt, steel main bearing caps. All this makes a lightweight, rigid, block structure offering good durability and reduced friction.
Chrysler borrowing from that block design for V8s in its own full-sized trucks and performance cars says much about GM's engine technology. Some might be disbelieving of the Gen 3/4 block being so inspiring to a competitor but, if you ever see the two short blocks disassembled, side-by-side on a bench; the influence will be obvious. Imitation is the best form of flattery.
There are improvements in the LS3 block. Compared to last year's six-liter, the liners have .084-in larger bores, its main bearing webs are about 20% stronger and their "windows", which enhance "bay-to-bay breathing" in the interest of oil control and reduced parasitic loss, have been somewhat enlarged.
"When the block is honed, the bottom of the honing tool needs clearance so it doesn't contact the block below the bore." Rydzewski (Corvette engine ace, both figuratively and, as he's the LS3's Assistant Chief Engineer, literally. Rydzewski worked on Small-Block as far back as 1993) told the Corvette Action Center. "Before the honing operation, the block is machined in that area to provide (hone over-travel) clearance. The resulting surface geometry has a big impact on the block structure. The hone over-travel clearance used to be machined with a 3-mm radius. With LS7, to get more strength in that area, we changed to a more gentle, 8-mm radius. That was a big durability enabler at the LS7's power level. When we got into the LS3 finite element analysis (FEA), we found our safety factor needed some improvement, so we applied what we learned about LS7's hone over-travel cut-out. We were able to increase the radius to 10-mm which was worth about a 20% improvement (compared with the LS2 and '07 L92 blocks) in the strength of the block structure in that area."
These changes to the main bearing webs in an LS3 case (right) might not look like much, but they make a huge difference in the strength of the lower end of the block. Image: Steve Constable/GMPT Communications
LS3's nodular iron, rolled-fillet-journal crankshaft is similar to LS1/2/6 parts except for counter weights altered to rebalance the engine for a slightly heavier piston.
The shotpeened, powdered metal, hot-forged, steel connecting rods are the same as what was in LS2 except for a new rod bolt. Rod length remains 6.1-in. The rods are "net shape" so post-production machine work for balancing is not required. As before, they're "cracked rods" which means that, to simplify manufacturing and enhance fit between rod and cap, the big end is fractured in half rather than machined. The rods' small ends are bushed for full-floating wrist pins.
Rods with cracked or "fracture-split" big ends are common on modern engines. The fracturing creates a unique interface that "locks" together only one way and does so very precisely. The more accurate interface ensures a uniform big end diameter and shape. Image: Author
Starting with the LS2, Gen 4 V8s use a full-floating wrist pin so the rods are silicon-bronze bushed and the bushing has an oil feed groove milled into it. Image: Author
The LS3 rod bolt uses two different thread sizes and diameters to control and localize bolt stretch. Image: Author
The new rod bolt is made of stronger material and meets the same grade 12.9 specification as do LS7 bolts. The better material allows clamp load at the rod cap interface to go from 47 kilonewtons to 50kN. The design of the rod bolt was changed, too. ""An alignment feature was added to the shank of the fastener," John Rydzewski told us, "and unique threads are rolled into a short length of the shank.
"An (old style) connecting rod bolt will have deformation along the length of the fastener which results in concentrated stress at the first engaged thread. Since unengaged bolt threads are able to stretch freely while engaged threads are constrained by the threads in the rod, the first engaged threads are more highly stressed
"The new Small Block bolt is similar to a 'necked-down' fastener, where the bolt stretch/deformation will be focused in a portion of the length of the bolt not near the first thread of engagement. Compared to the standard threads (on the rest of the new style bolts, this area has) a larger outer diameter which provides alignment to the rod hole and they have a smaller minor diameter which provides an additional benefit of isolating much of the plastic deformation from yield to this rolled section of the fastener. Therefore, the concentrated stresses at the first thread of engagement will be less and the overall joint safety factor improves."
In the early LS1 years, because of the short-skirted piston necessary in the Gen 3/4 engine family, cold piston knock was a customer pleasability issue. Since the '02 LS6, Corvette pistons have had a polymer coating on their major and minor thrust surfaces-the gray area on this LS3 piston skirt. At the end of the break-in period, a lot of the polymer and a slight amount of piston material is worn away, leaving a very consistent skirt surface, a nominal (and tight) piston-to-bore clearance and hopefully, no cold piston knock. Image: Steve Constable/GMPT Communications
The LS3 piston and ring package is typical of what GMPT has used since 2002 in high-performance SBV8 applications, but with more groove "tilt" and higher oil ring tension. Image: Author
Here's a "bare" LS3 piston. The hard-anodizing adjacent to the top ring groove is a durability feature. While the oil drainback notches have been in Gen 3/4 pistons for along time, new are the oil drainback holes, two each on above the major and minor thrust faces, drilled into the piston interior. Image: Author
The underside of the LS3 piston. As the piston moves down in the bore, oil is scraped off the walls by the oil ring then is "flushed" down the oil holes and into the interior of the piston. Image: Author
More cutting-edge technology is in the LS3 piston and ring package. The piston is a flattop design, cast with a hypereutectic, aluminum/silicon alloy containing traces of copper and nickel. The compression ratio, 10.7:1, is down slightly from 10.87:1 in '05-'07. This piston is the same as the L92's 10.5:1 unit except for a valve relief the truck piston has for additional piston-to-valve clearance required by the L92's variable cam phasing. When the relief is removed, 0.2 compression is gained but, to get higher than 10.7 requires a domed piston, the cost of which was deemed unnecessary considering LS3 met its performance and efficiency goals at 10.7:1.
Ring grooves are machined with a slight upward tilt which was increased by 0.25° for '08. The top ring's tilt disappears as the ring land flexes under the pressure of combustion such that sealing and oil control are optimized. The other two grooves' tilt enhances the ability of the second ring and the oil ring to scrape oil off the cylinder walls. To further improve oil control, the LS3 piston has four holes drilled in its skirt, just below the oil ring groove downwards into its interior. These holes, two adjacent to the major thrust surface and two adjacent to the minor thrust surface, improve oil drainage from below the oil ring.
The top ring is the most critical part of compression sealing and, in an LS3, it's a pretty trick part with one of the tricks being a slight twist to the ring. Image: Author
With the rings in simulated position on a piston, you can easily see the hook-like, Napier-faced second ring. "Napier rings" are much better at scrapping oil off the cylinder walls as the piston moves down and that's the reason GM upgraded to them for 2002. Image: Author
Surfaces either side of the top ring groove are hard-anodized. The piston skirts are coated with the antifriction polymer introduced on LS6 for MY02. Interestingly, the pistons are installed with -2 micron (-.00008-in or eight hundred-thousandths of an inch) piston-to-bore "clearance"–a slight interference fit. During break-in, some of the coating wears away, leaving a nominal piston-to-bore clearance. LS3 pistons use new wrist pins having tapered inside diameters, an idea straight from the C5R race program and which reduces pin weight with no loss in strength.
Oil control at high rpm has been a challenge with Gen 3/4 engines. Since 1997, to that end, GM has tried several combinations of crankcase ventilation systems and ring tension. While, for '08, the PCV caries over from LS2; the ring package has, once again, been changed. The top ring is still moly-faced steel and "coin twisted," which means its shape in side view is slightly conical to improve the ring's sealing when under combustion pressure. The second ring remains cast iron with the "Napier" face introduced in MY02 and they both are 1.5-mm. wide with the same tension as before. The oil ring is still three-piece, two rails and an expander, however, to improve oil control, for '08, its tension was increased.
So.. if i were to be looking at stroking my VT, id drop in an LS3 with a 4" Crank (417ci i think) and just put in a big cam.
Thanks for that Tom it's a good read, looks like they have a few areas of improvements over the ealier motors. Can you still use ya old exhaust or do ya need new headers with the ls3 heads.
SIG-054... if you stroked your LS1 though to 383, or used an LS2 block and stroked it to 408, it would come to about 8-10k but would have forged everything (rods, pistons, crank) plus you'd put in lifters along with other aftermarket stuff and it would be a lot better performance setup than an LS3 for the same price. I do understand what you mean about the LS3 being a better stock engine compared with a stock LS1, but i cannot see an LS3+cam being better than an LS1/LS2(block)+stroker+cam+heads for performance. For street manners yes, LS3 will be better. I went for a drive in an LS1 383 stroker + big cam and stock ported heads, manifold T/B, twin 3" system, and it was pulling about 330rwkw. The thing absolutely flew, would wheel spin if you planted your foot at like 40km/h. The owner said once he stroked it after camming it, power increase was huge although peak power from dyno figures only minimally changed. Can't really compare an LS3+cam at 330rwkw to a stroked LS1+cam+heads at the same (peak) power.