5 Biggest, Baddest LS Motor Configurations Above 6.2 liter
The most commonly available big LS motor is the 6.2-liter that came in trucks and vans, but for the right price, you can go much bigger. Let's look at just how big and bad an LS motor can get.
1. Various Sources - 408ci 450-625hp
If you are building a new LS based motor for a project, this is probably where you should start. Take a 6.0-liter truck motor and bore it .030" over, then install a new 4" stroke crank and you get 408ci or 6.7-liters. With just stock parts hanging on a short block, this size you are going to have more than 400hp. Aftermarket companies like ATK are rebuilding junkyard truck motors and selling them ready to drop in with 600hp for less than $10,000.
2. Various Sources - 427ci 500-650hp
There are any number of companies out there making 427ci LS based motor, including Chevrolet themselves with crate versions of the LS7. The bowtie motor is rated at just 505 hp but can be expected to be as reliable as if it was factory installed in a Corvette. Blueprint Engines has custom built 427ci motors rated at 625 hp, for less than $10,000, with a carburetor or fuel injection. Step up to Texas Speed and Performance, and you get a 635 hp motor, for about $15,000, but it is complete including a custom built wiring harness, computer, and more. Legendary name Lingenfelter also has a 427 for you, for over $20,000, but you get what you pay for and you are paying for 650 hp, race winning performance. If you are the do it yourself type, you can build a 427 with just a custom crank from a company like Scat, plus a 6.0-liter truck motor.
3. Chevrolet Performance LSX 454 - 454ci 627hp
The LS motor is considered a small block, but thanks to modern casting and metallurgy, it can deliver as much displacement and power as an old big block. The 454 cubic inch LSX crate motor, direct from Chevrolet, puts out 627 horsepower at 6300 rpm, and 586 lb-ft or torque at 5100 rpm. It will run good on 92 octane fuel, so you can use it in a street car (unlike the even more extreme LSX 454R), though it will cost you as much as a good used car, with an MSRP of more than $13,000.
4. Goodwin Competition - 500ci 730-800hp
No you are getting up into the harder to find displacements, often needing a special tall deck block and stokes of more than 4.5" Goodwin Competition offers, not just several 500 cubic inch LS based motors, with up to 800 hp, but also a mildly tuned 510 cubic inch motor with more than 775 hp on pump gas. There are other companies custom building motor like this and bigger, but this is a good example and will set you back about $25,000.
5. Racing Head Services Tall Deck Block - ???
RHS has been hard at work making a block based on the LS architecture that will deliver truly huge displacement. How big can it go? How much power can it make? People are still building them and finding out, but it can be built to over 510ci fairly easily with the right crank. The block itself will set you back $5,000 or more, but if you want to play you have to pay. LSX magazine did a very good article with all the details here.
for help keeping your LS1 power machine in tune, check out the how-to section of LS1Tech.com