LSX vs Dart vs OEM Aluminum for 1000+ whp
 

All opinions are welcomed here.

LSX 427 vs Dart 427 vs Aluminum 416 for a boosted application making north of 1000whp.

I am leaning towards a 6 bolt application, am not concerned with the extra weight of cast iron.

Price does factor in, meaning is the LSX block really worth the additional investment vs the DART block? Should I consider the aluminum 416 at all?
I don't mind spending the money, but don't want to burn it for no good reason.

Car will see track use such as road race and a bit of drag racing. It will however spend most of it's time on the streets.

Thanks!
Brian

1000-1100whp is where we start to see distortion of the bores in a factory block. It's not a magic number or firm line in the sand, it depends on the power adder, how you use it, etc, but at some point the block itself does become a liability. 4 bolt heads also start to show their weakness at similar power levels.

So, when you say north of 1kwhp, that sounds like a maybe yet to be determined amount, and maybe it'll get turned up over time. To me, the right choice is then the Dart block for it's overall strength and quality, with lots of options to get it how you want it for your build. Load it with a quality 4.125x4.000 rotating assembly, good 6 bolt heads, and prosper.

Thanks Andrew!

I do have a target of 1100-1200whp as the ceiling. Doubtful I would try to go higher than that, at least on this setup. If later on, I decide to go full race, then perhaps. It is a turbo setup, but certainly wont live at max effort all the time.

I feel pretty certain that I'm going to want a 6 bolt head setup to reach my goals. I see you made no mention of the LSX block, any reason for that?

ATM I have no preference between the LSX and the Dart block. And seems to be a good mix of both in the LS community. That is why I am gathering opinions on it. To understand why people go one way vs the other...

:happy0180:

How can you not consider the additional weight of an iron block when using the car on a road track? The only way I would consider an iron block would be for drag racing only, even if I had to reduce my power goals.

I lean towards the Dart for higher quality and strength, fitment of factory parts (pan, oil filter, accessories), priority main oiling, and options for bore size, deck height, cam position, main style, etc to suit just about any need.

Agree that 6-bolt heads should be on your list for sure if the eventual number is probably more like 1200whp. I'd fill an LS Next 4.125x4.000 with a Callies Magnum crank and Ultra H-beam rods along with a piston matched to the head type and volume to hit my target SCR

^This^ Take it from someone who did this and has some regrets. Pay someone else like Thompson or even TSP to put a short block together for you. I bought an unfinished LSx block, thinking I'd save money on the build only for machine shop to beat me up and for TSP to tell me K1 rods might let go at 1000hp. Point is SPEND THE MONEY and build it for MORE than you expect to use. Its peace of mind and gives you the ability to grow. The statements "boost is addictive" and "you get used to the power quickly" are wildly true. You will want to turn it up and up and up. Buy the strong expensive stuff and do it once. As far as Dart vs LSx. I think the Dart block I was looking at was more expensive so I went with LSx. I found cracked cylinder walls in the stock block, got mad and bought the LSx the next day. Also DO NOT FORGET you cannot use stock headers or you have to make a modification to them if using 6 bolt heads. I mention that because I think you are using the AGP turbo kit which utilizes the stock headers.

*Also you will not care or notice the extra 100lbs on the nose of the car, you will however be fighting to find traction if living on the street. I have struggled to make 800whp useable. Good luck with it bro.

I understand your concerns. I have put a lot of thought into it actually. Being as how I don't race competitively, I'm prepared to make that comprise.

Valuable information and I appreciate you name dropping components like that.

I am leaning towards the Dart block.

Appreciate the knowledge you have! I will not assemble this, I will purchase a short block from some respectable builder. I know my goals, just trying to get advice and knowledge to make my best decision when I pick a builder.

Not my first boosted build, but is my first boosted gen 4 build. Boost is a terrible addiction. :smiling1:

And yes, I am in the AGP camp, for now anyways. :happy0180:

Might wanna check with these guys as well if you are considering a build. I only mention BTR because i love there intakes and everyone speaks highly on the cam kits they offer. I have a BTR trinity intake and a stage 1 centrifugal cam saved in my cart...

https://briantooleyracing.com/btr-as...ort-block.html

Thank you sir. I too have both the trinity and the equalizer in the cart, it's a hard toss up between the two.

BTR is one of the top on my list. :w00t:

If we're talking about having a builder put the short block together... I humbly suggest that here at GPI, that's what we do! We work with each customer individually to understand needs, budgets, and goals, come up with a solution to meet all of those, and then we have the vendor relationships and machining, and engine assembly facilities to put it all together. We are dealers for all of the aforementioned parts, as well as many more options we could tap into as needed. We'd definitely be happy to work with you - if that's something you're interested in please feel free to reach out directly to andrew@gwatneyperformance.com

Don't worry Andrew, you guys are towards the top of that list too! :cool:

My list isn't that long so far, still researching... but Thompson, TSP, BTR, and GPI are top contenders. I am considering Mast also. I'm not aware of any reputable builders in my area here in the southeast.

To OP:

Hell dude, let his shop do it. I didn't realize they did this when making my previous post. He is giving you good advice. Price will probably be about the same no matter who you go with and this guy is here helping you out.