Looking to do a fully billet LS3 rotating assembly.. 376, 418, or 427?

[sheplex02]

Going to be doing a billet LS3 build soon (billet crank, billet I-beams, high compression pistons). Biggest trouble I'm having is deciding displacement. The goal for the build is to have a fast revving engine with a redline as high as possible with power being 550 or higher. Cost is going to be to different between the different sizes, but that's not my biggest concern. my concern is what would be some of the pros and cons of each. The larger 427 displacement will have higher torque, but I'm worried about possible issues with heat. On the other hand, the smaller 376 displacement will be lighter and thus should climb RPM faster. Would that then make the 418 the best choice?

I will be doing transmission mods, carbon fiber driveshaft, and other drivetrain mods to support the engine properly.

[hou30guy]

I have a 408 and its a beast so i know the 418 gonna put in work

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[zz430camaro]

A 418 would be the best bet if using a LS3 block to get to 550 rwhp. GPI performance can help you with getting all that stuff, they just did a similar build on here.

[Jason 98 TA]

Call Texas Speed. You have tons of options. Everything from a 418 toa 468! I think a 454 or 468 short block would be awesome and make tons of power.

[sheplex02]

Originally Posted by zz430camaro

A 418 would be the best bet if using a LS3 block to get to 550 rwhp. GPI performance can help you with getting all that stuff, they just did a similar build on here.

Yeah, it's gonna be a LS3. I want this to be as plug and play as possible for the camaro. I read the GPI build, looks like a great recipe to follow! I've got a few things I'll be doing differently.. but it is great to see that I will most likely be getting upper 500's in horsepower and low to mid 500's in torque!

[zz430camaro]

Originally Posted by sheplex02

Yeah, it's gonna be a LS3. I want this to be as plug and play as possible for the camaro. I read the GPI build, looks like a great recipe to follow! I've got a few things I'll be doing differently.. but it is great to see that I will most likely be getting upper 500's in horsepower and low to mid 500's in torque!

You are limited with the LS3 block with stock cylinder sleeves on the bore size. A 418 with the right heads, cam and compression will get the job done. I was also confused when you said "billet crank". A forged crank is way cheaper and can handle more power than you can throw at it.

[sheplex02]

Originally Posted by Jason 98 TA

Call Texas Speed. You have tons of options. Everything from a 418 toa 468! I think a 454 or 468 short block would be awesome and make tons of power.

That's who I've been looking at so far. Great company and so many parts available! I'm not sure if I want to go as big as 454 or 468. At some point I'm going to be losing certain characteristics that I find to be more important than a little more power. The most powerful NA LSX I have seen was almost 650 to the wheels, but it took noticeably more time to climb those revs than a LS3 with a stock block and a great heads package with a little about 480 to the wheels.

[zz430camaro]

Originally Posted by sheplex02

That's who I've been looking at so far. Great company and so many parts available! I'm not sure if I want to go as big as 454 or 468. At some point I'm going to be losing certain characteristics that I find to be more important than a little more power. The most powerful NA LSX I have seen was almost 650 to the wheels, but it took noticeably more time to climb those revs than a LS3 with a stock block and a great heads package with a little about 480 to the wheels.

Texas Speed sold me a great cam, could not be happier. I would use any of their stuff.

[sheplex02]

Originally Posted by zz430camaro

You are limited with the LS3 block with stock cylinder sleeves on the bore size. A 418 with the right heads, cam and compression will get the job done. I was also confused when you said "billet crank". A forged crank is way cheaper and can handle more power than you can throw at it.

Thats the other issue I'm thinking about.. I figure if I use a torque plate and just hone the cylinder out .001 for a perfect round and run some really good gear, it wouldn't be worth doing sleeves and stroking. That way I can save some money and time.

The reason for the billet crank is weight savings. I know its not much, but the billet crank I'm looking at from Callies is about 2 pounds less. Less weight, faster revs.. right? lol

[sheplex02]

I'm wanting to run a 4.00 crank due to the nature of the LS3. From what I've read everywhere, the 4.00 is the perfect size for the engine.

I understand that the larger displacents will get that power level "easier".. but would it be worth the added cost vs power gains (spend another $4,000 for an additional 30-45 horse power)

[zz430camaro]

Originally Posted by sheplex02

Thats the other issue I'm thinking about.. I figure if I use a torque plate and just hone the cylinder out .001 for a perfect round and run some really good gear, it wouldn't be worth doing sleeves and stroking. That way I can save some money and time.

The reason for the billet crank is weight savings. I know its not much, but the billet crank I'm looking at from Callies is about 2 pounds less. Less weight, faster revs.. right? lol

All depends on how much cash you have!

[frankwjr]

3.90 is actually perfect...IMHO.


peace

[christianchevell]

The weight savings your so worried about to translate into less material in the crank are something most do not think about, usual place to loose some weight is in the flywheel with a aftermarket one...……….a lot more rotating loss of power; heavy versus light weight...…. but most go with the stock heavier weight for a hot rod as it keeps the momentum between shifts for a manual and is great for a daily driver also.... Frankly most go with the 416-418 area though the difference in stroke is so small for a larger 427-428 but playing it that much safer for the travel is good. Also you will want to know the compression with the slugs in the hole as if you plan on a future FI build too much compression makes it harder to do if your leaning that way. Spinning up to higher revs faster....not so much.... and raising the rev limit not so much done for the ls engines unless your investing in top end upgrades, trunnions, rockers etc....for higher revs and the fact most aftermarket cams are way into loosing power and falling at higher revs and theres no point going there to actually slow down stupidly......and you want to watch the torque..its what moves you, HP shows how hard the engine works in efficiency making that torque..it moves jack squat..... and that's why a stroker is done, that 40-50 ft lbs all along the board it matters bigtime to make it a beast versus a noise machine that's hard to burn rubber with. We drive a heavy Chevy.

And BTW your ls3 block is with cast in sleeves your not going to find any sleeves to install and no one to do it its a throw away block...max over-hone of .020, and you will want custom pistons and rings for the purpose using it for to fit the over hone....cleaning up anything .001 most likely a very very low mileage engine. Stoking it involves clearancing the bottom of the sleeves that can run into the bolts on the con rods etc.... also clearancing the windage tray, and MAST sells one I had to clearance further. The cylinders sleeves stick out unsupported from the casting of the block at the bottom of the bore. I recommend the Monster lt1s clutch to people and others have also its great for stock feel and uses the stock slave. But most can use stock clutch until it some day wears out/fails... And actually we are lucky to run the ls3 not a ls7 that can only be overhoned .005 and cost twice the price...WTF not worth buying IMO also making it a much more disposable block.. No heat problems here just the usual slow start problem of engines with headers......and I daily drive ……. if your going to circle track race you want to shift in the top of the power curve area and the lighter flywheel can help for fast shifts and less power loss but as I said most just go stockish flywheel for the use of the engine as; momentum matters and a object in motion tends to stay in motion and going billet something I never considered for the forged parts. You may want to think about clearance for the pistons and how large a cam you can use...and whats the average power curve look like for the cam as changing the rev limit to 7 grand with your torque falling off around 5500 and the HP 6000 why go that high to just loose on the short track to someone shifting more in the power band and yes you want a shit light like the aftermarket Speedhut I use simply plug and play....

[zz430camaro]

Texas Speed will re-sleeve a LS3 block. You can supply a good block or buy one from them.

https://www.texas-speed.com/p-5572-t...-outright.aspx