How LS Motors Compare to Early V8 of Similar Size (photos)
In the mid-90s, Chevrolet made a general switch from the classic V8 engine design to the more recent LS motor. Looking at the two of them, how do they compare power-wise, comparing similar displacements.
1. 350 cubic inch LT1 Corvette - 1970-72
The 350ci/5.7l Chevy V8 is perhaps the most popular motor of the classic first generation small block motors. The most powerful version was the 1970-72 Corvette LT1, rated at 370hp in the old system, 330hp by the new net rating in 1971, or 255hp net with lower compression in 1972. These were the last of the fire-breathing small blocks before unleaded gas lowered the compression, and smog laws took out all the camshaft duration. It would be another 20 years until a small block made this much power again, and that was the tuned port injected LT1 of the 1990s.
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2. 5.7 liter LS1 Corvette - 1997-04
The modern cam in block V8 era dawned with the 5.7 liter LS1 in the 1997 Corvette. That first year power was rated at 345 horses, 90 more than the old LT1 from the 1970s, and 45 more than the 1996 version, and it only went up from there. All aluminum, with a composite intake, and less moving parts, the new tech LS1 motor weighed less and fit into a more compact space too, thanks to the redesigned accessory drive system.
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3. 283 cubic inch Ramjet Corvette - 1957-61
It may not seem like a lot now, but the 1957 Corvette with 283 horsepower from its fuel injected small block was a huge deal at the time. Later, with tuning and development of the Rochester Ramjet mechanical injection, the car developed more 315hp, by the old SAE gross testing methods, which if we use the LT1 motor as a guide would be about 275 net. These ancient motors are surprisingly quick to rev despite the heavy 1950s internal parts.
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4. 4.8 liter LR4 Vortec Silverado/Sierra - 1999-06
Typical for GM, the LS motor was cast in iron to make it cheaper and more durable, and shared with the truck line in 1999. The littlest of these LS motors was the 4.8-liter LR4 used in the full sized vans, big SUVs, Chevy Silverado, and GMC Sierra, which made 255-295 horsepower, depending on the year. These sweet little motors have proven capable of over 500hp on boost, with stock internals, and were even available with a factory 5 speed manual on the trucks. It's a testament to how well engineered the original 283 motor was that it made similar power and with 10 fewer cubic inches.
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5. 327 cubic inch L84 Ramjet Corvette - 1962-65
For a long time, until the LS6 in 2001, the 1964-65 327 cubic inch fuel injected V8 in the Corvette was the most powerful (per cubic inch) small block Chevy made. Using a lumpy cam, lots of compression (11:1), and needing leaded gas, the L84 motor was the final evolution of Zora Duntov's small block development program. Of course, using the SAE gross rating, these motors were claimed to produce 375hp in their ultimate form.
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6. 5.3 liter LS4 Grand Prix GXP - 2005-08
Comparing the top line 327 with the run of the mill, GM workhorse 5.3-liter isn't really fair, but there was never really a fully tuned factory version of the 5.3. GM makes 5.3-liter V8 motors in iron and aluminum, for cars and trucks, and in front and rear wheel drive setups. The best version of these motors was actually installed in SUVs and rated at 320hp (while the FWD sports sedan Pontiac pictured above had only 303hp) which corrected for net vs gross ratings, is not too far off the old fuelie Corvette rating. You can see why folks are pulling LS truck motors out of junkyards instead of rebuilding smog era 350s these days.
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7. 427 cubic inch L71 Corvette - 1967-69
This is a big block car but has nearly the same displacement as the 7.0 liter LS based motor in the modern Corvette. Depending on which version you ordered, these motors were rated at anywhere from 390-435hp, all with 460 lb-ft of torque. Thankfully, since big block Corvettes are still hugely popular, people have tested stock Vettes and motors with the modern method and found they make about 376 SAE net horsepower in their most potent stock configuration.
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8. 7.0 liter LS7 Corvette Z06 - 2006-13
The LS7 may go down as the ultimate naturally aspirated GM V8 motor ever, with its insane 505hp and 470 lb-ft of torque. Not only do these motors make more power than the Can-Am race spec aluminum big block ZL1 from back in the day, the C6 Corvette would run ring around the C3 Vette on a road course. Sure these motors have to be hand built like a race motor to be able to do it, but to get over 500hp with a full factory warranty, and be able to do it for 100,000 with proper maintenance wouldn't even be dreamt of back in the 1960s.
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for help with the maintenance needs LS-powered car or truck, check out the how-to section of LS1Tech.com