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LS high boosted engine!

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guys i made an engine with a ls2 almunium block and ls3 heads, the engine is fully strocked running on a 4 liter supercharged. Car made 750WHP on 0.8 bar of boost. What i want to know is how much more boost can i go on this almunium block ( i am aiming for 1200+ whp where i think i will need atleast 2.2bar+ of boost ). Also a guy advised me to install sleeves on the engine, so i wanna ask should i install sleeves, which are the best sleeves for this application and where is the best shop to fit them. Also if anyone could suggest the best strocker kit for this application i would be greatful


Probably not the best forum to ask those questions - there are a LOT of LS engine and car ones that should be able to help more. Heck, there is even a magazine devoted to this engine - could do a lot worse than picking up some (back) issues and see what other people are doing?

Anyway, thoughts...

First, very good power from the beastie and, from what I gather, close to the limit for the alloy block i IIRC, the sleeves will move in the block.

Sleeves are available from www.lasleeve.com and www.dartonsleeves.com - the latter can supply fully prepped blocks or short blocks - might be worth a call?

Depending on your budget, might be worth checking out some of the tall-deck block (this is different from long block) versions available from multiple sources - some are available in short block form with stroker crank setups and lower comp' ratio pistons if not running race/alcohol - might be a viable option if you sell your old one (or want to keep it as a backup). You can even build something like this 502 CID beastie (might want to keep the bore a little less for cylinder wall strength, if needed, with high boost?) - https://www.lsxmag.com/tech-stories/engine/engine-build-rhs-backed-700hp-ls-big-block?

There are different ways of getting xxx power, have a good think about how the engine is going to be used as it may be worth paying a bit more to get something that provides what you need, for your application.

^ agreed. First you gotta ask: What's your budget and how much more power do you really need/can you actually use?

What i need is to upgrade an almunium block and make it go up to 1300 whp ( 2bar+ boost ). Why i need an alminium block? Because the competetion that im building my engine for doesn't allow lsx blocks which are metal.


When you say you have an LS2 aluminum block, do you mean you have an OEM (stock) block? Since you want to make 1200 horsepower, you shouldn't even bother trying on a stock block. It's just a waste of time. Sell what you have (you're going to need all the money you can get) and buy a built one. AMS for example sells a built block with matching pistons. See link below. For your situation you would want to talk to them directly.


Aluminium (AKA aluminum) IS a 'metal' - you mean cast iron? Funny thing is it is usually the other way round. Do you mean it has to be a factory block as supplied in a specific vehicle - that would make sense. Are any aftermarket blocks also banned, that would limit you rather.

Again, your best option is probably to purchase a complete bottom end - short block - from a reputable builder and, as a tall block version allows a longer stroke, that is what I would be looking at (but you may not be allowed those?) - make sure they know you will be running it boosted, though, and the fuel you will be using, as the piston design (nominal compression ratio) will differ with the fuel - especially when used with forced induction.

I can't recall if those heads are the 'square' or 'cathedral' design - the former will make more power but, either way, having them optimised (ported) by a reputable machine shop/specialist will always be a help - and the bigger the engine, the more difference it will make. If you decide on a long block - cylinder heads also supplied with the short block, you could get the best flowing ones you can.

Not sure if that supercharger will support the airflow and boost for that power level - have you checked?

Forgot, reminded by latest Leroy video, is your engine a 4 or 6 bolt head arrangement? A 4 'might' be marginal, even with ARPs and good gaskets and machining the engine block and heads for 1/2" studs may be advisable. 6 Bolt spreads the load better and 'should' be OK with a stud kit and good gaskets.

If you could post the rules the engine has to abide by, or a link to them, it would help.

There are a variety of aftermarket aluminium blocks available that will support the sort of power you're aiming for. Perhaps something like the Dart LS Next would be a good option to look at.

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