Hello all, im new here, am new to the Ls world, have always been a big cube carb engine kind of guy. I have a 56 chevy truck that im planning on doing a Ls instal, im trying to find a wrecked camaro or vette to get an Ls3 and computers from.....im looking to build a 427 out of it, but i want reliablilty with it, ive read the walls cant be bored to far without compromising the cylinder walls, and i know they have stroker cranks that do the trick with boring but i hear they start to knock at bdc. So im trying to find the middle ground of stroker crank and boring out the block. Im trying to get around 600hp to the crank.

 

In practice the 4.065 bore LS3 block is typically just cleaned up with a .005 hone for a 4.070 bore. The thickness of the LS3 iron cylinder liner and LS2 in theory allows a similar over bore but core shift that occurs during casting makes for an uncertain result. Typically up to .020 on either should be good. Normally, minimum clear up is what most do going .005 or maybe .010 over as needed.

Some LS2's can go .060 or 4.060 bore and some LS3 can do 4.1 or ~ .035 over based on what I've read. Unfortunately, sonic checking the block to find out exactly how much one can over bore by isn't a simple task. The stock liners have reinforced rings in certain areas that make getting an accurate reading difficult.

Due to the fairly short cylinder sleeves in factory blocks correct piston choice is key to avoid piston rock at bottom dead center with 4 inch or longer stroke cranks. The piston needs to have a compact ring package and the right type of taper. Wiseco, Diamond and I believe Summit have this down pat with with their LS stroker piston design. Be sure to work with a knowledge engine builder that understands what's needed to avoid a piston rocking oil burner.

I have a 383 LS1 & 416 LS with 4 inch cranks and Wiseco pistons and no piston rock or oil burning issues. The 383 LS1 has 10,000 miles and a lot of fun rpm The 416 about 3,000 miles.
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Some will say a piston rocking oil burner will happen if going over 3.9 on stroke on a stock length cylinder liner. That's not been my experience but both of my engines were built by knowledgeable engine builders that were well informed about the piston rock issue and picked the correct Wiseco piston.

Scoggin Dickey offers a LS3 427 with a 4.070 bore and 4.10 stroke.
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Horsepower Research, Erik Koenig's new company excels at building stroker engines and can probably help with your 427 or a 454 build. Lingenfelter, Texas Speed, Thompson Motorsports, Bischoff Engine Service, Reher-Morrison and many others are top notch engine builders that can help too.

Best wishes with the build.

 

How about the L92 conversions. Whats the cost difference from finding an ls3 and turning it into a 427 or finding a L92 and converting that, how much does it actually cost to turn a L92 into a pump gas N/A 600hp engine.

 

OK.....the 429ci LS3 in my 2014 SS just went past 40K miles; the first 35K miles were hydraulic roller.

Best dyno I got out of it was 551HP/518TQ at the wheels. So yeah.....durability and 600HP crank is VERY doable!

Built by Texas Speed. www.texas-speed.com/p-307-tsp-427-or-429-cid-ls3l99lsa-long-block.aspx

KW

 

Could just start with this and take a lot of the guesswork out of it....

https://www.summitracing.com/parts/m...make/chevrolet

Or this....even comes with a computer setup for the motor already. And the drive by wire gas pedal assembly.....

https://www.summitracing.com/parts/m...make/chevrolet

God, these motors are fng expensive.

 

There is not a whole lot of advantage to the 427 over the 416 LS3 speaking in terms of HP/TQ in a typical 6500RPM hyd roller street set up. We build a good bit of them for air boats and rock crawlers that need all the LOW tq possible and they work pretty well for that. We do still build for cars as well and while the useable tq curve is a little lower on the RPM scale it is not a huge change from the 416. As for lifespan of the motor, they can actually be pretty long in the 427 if built and treated right. We have on in one of our managers cars that is on track to break 100K miles in the next few months. It is a true daily driver that is about 4 years old. He is pretty hard on it but still hanging in there like a champ. It is just recently beginning to show signs of wear and will be coming out once it breaks the 100K mark for inspection and freshen up. If we can help you in any way making your decision please do not hesitate to reach out to us.
Thank you,
Kyle
972-853-2450

 

Wiseco has a nice piston for the 4.100" stroke crank for stock GM blocks. It doesn't have the typical rock at BDC from being pulled too far out of the sleeve. So they last a good long while.

I think in the 56, I'd want to tune it for more torque and the 4.100" stroke is a nice idea.

Horsepower Research in Texas has a 442 LS3 build with a 4.25" stroke crank. That requires a lot of special parts... special machining of the block, shorter rods (I believe they are custom 6.000" parts), a custom spec piston with a shallow ringland and different skirt design, and a smaller base circle cam. That would be a very interesting motor for what you're wanting to do. They build that for road racers that need a lot of midrange torque and aren't looking to spin past 6500.