Help planning 427LSX FI Build.

[Steck]

Strength isn't an issue with the LSX block. The block itself can be used as a structural member in a chassis as a matter of fact. Weight is the big killer. It carries about a 80lb penalty.

[HufferSS]

Originally Posted by CC Performance

Iron is more durable than aluminum

aluminum and iron expand at different rate ( heat) think housing and bearings

For big FI HP I'd go with iron if it were my personal car and didnt care about the 125 lbs of extra weight....

The money isnt close either... $4600 for the RHs and $2250 for the LSX

The LSX block requires a lot of "extra" to get it up to par with the RHS block.....in my opinion....... and iron vs aluminum....it doesn't matter as long as the aluminum is capable of handling the power required. Is Iron stronger....maybe but as long as the aluminum is strong enough then the point becomes moot.

[HufferSS]

Originally Posted by CC Performance

Yes the RHS block is a great block but metal properties are what they are.
Tell me what the advantage of the RHS block in this application is ?
You say it would take a lot of money to bring the LSX up to par... what needs to be done ?


BTW we're building a 506 cid RHS block engine right now as well.... so we do use the block...LOL

Well I am not an expert like you but from what I know it needs to be bored considerably to get it near final bore size for most big inch motors.....it also has smaller 10mm main studs while the RHS block uses 7/16 studs.....plus it's heavy!

[Steck]

Originally Posted by HufferSS

Well I am not an expert like you but from what I know it needs to be bored considerably to get it near final bore size for most big inch motors.....it also has smaller 10mm main studs while the RHS block uses 7/16 studs.....plus it's heavy!

You can drill and tap the holes in the LSX block to be bigger if need be. Yes, it has to be punched out to get the displacement up higher, but that's not $3000 in labor and machining. My entire short block with LSX block, Dragonslayer crank, Lunati billet rods, and JE 2618 pistons (plus other stuff) was $6500.

Look at IPS... They ran a ton of power in atomicfusion's car with an X block. It was made to take a ton of power. It is heavy, but it's also cheap (cheap being a relative term).

[HufferSS]

Originally Posted by Steck@Craven

You can drill and tap the holes in the LSX block to be bigger if need be. Yes, it has to be punched out to get the displacement up higher, but that's not $3000 in labor and machining. My entire short block with LSX block, Dragonslayer crank, Lunati billet rods, and JE 2618 pistons (plus other stuff) was $6500.

Look at IPS... They ran a ton of power in atomicfusion's car with an X block. It was made to take a ton of power. It is heavy, but it's also cheap (cheap being a relative term).

I didn't insult your sister here guys.....I'm just saying that the LSX block isn't as good, in my opinion, as the RHS block. Sure you can drill and tap it...which costs money, sure you can bore the shit out of it but that costs money and at the end of the day it's heavy. It's not a bad block....in fact is a sweet deal at the price point but if you want the "best" then in my mind it is RHS.

If you want the best bang for the buck then it's an LSX block....maybe.

[HufferSS]

Originally Posted by CC Performance

LOL... I'm not an expert...hahaha but I do this all the time as well....
The extra money you spend on the RHS block would be better off spent on the crank to be honest. ( CCW) The RHS block is great dont get me wrong but the LSX block was created for this application. If its a road race application and the rpms are high and sustained then its a different story.. the RHS wont have windage issues and has advantages but for big FI power the LSX block is rated to 2500 hp in proper form.
I havent seen a rating on the RHS block as far as that goes.... cant find one to post.. ?

I went with the Dragonslayer crank. I haven't seen a rating on the RHS block either but I would imagine it has to match the LSX block and I won't be anywhere near 2500 horsepower.

I could not imagine having 2500 horsepower and 10mm main studs....although I guess even 7/16" main studs seems tiny at that power level.

[Steck]

Originally Posted by HufferSS

If you want the best bang for the buck then it's an LSX block....maybe.

There's no maybe.

And if you're using ARP fasteners, I wouldn't sweat the 10mm studs.

[HufferSS]

. It's funny how divisive this topic can be...not so much here but say on a forum like the bullet. I always find it ironic that guys will drop 3 or 4k on a set of lightweight wheels to save 100 lbs but to spend 2k more on a block to save more.than 100lbs sounds ridiculous to them.

People are funny.

[Craven Performance]

Originally Posted by HufferSS

. It's funny how divisive this topic can be...not so much here but say on a forum like the bullet. I always find it ironic that guys will drop 3 or 4k on a set of lightweight wheels to save 100 lbs but to spend 2k more on a block to save more.than 100lbs sounds ridiculous to them.

People are funny.

I don't get it either, and for alot better block IMO.

[Steck]

Rotating/unsprung mass is a little different.

[HufferSS]

Originally Posted by Steck@Craven

Rotating/unsprung mass is a little different.

Of course it is.....but the same concept applies to other parts too. We justify what we want to justify.

[Squintz Palladoris]

Originally Posted by HufferSS

Of course it is.....but the same concept applies to other parts too. We justify what we want to justify.

Very True

[HufferSS]

Originally Posted by CC Performance

No, you dont understand. Taking weight off the crank/using a center counterwieghted crank is not the same as saving weight on the block.. it doesnt equal the same results.. not even close..
Yes the RHS block is king of the hill but in a FI application the LSX will do the same for less. You can beef up all the studs and fasteners and its still a lot less money... money that is better spent elsewere.... iron is more durable than aluminum.. even the almighty RHS block is still just aluminum.. bunch of good features and allow for a massvie stroke and big rpms... but boost isnt about big rpms when your dealing with big cubic inches..... do you need the block is the question.. If I had an unlimited budget I might not care but that $2500 difference if appplied to the crank is better money spent.

You are arguing a point that nobody else is arguing....taking weight off a center weighted crank?? It depends on what you think alot is...by the time you prep an LSX block to be similar then it is much more expensive than 2300 dollars.

That's a fact.

Now whether popping an extra 2k for an RHS block is a good idea....is up to the person building the motor. Most people who would even consider an RHS block are not exactly budget shoppers.

I don't care to argue it all night long.....as I said once already RHS is kin fo the hill in my opinion.....yours might vary.

[LSX-80MM]

There's just a major cool factor to having "CHEVROLET IRON". And the strength and durability far "OUTWEIGHS the RHS for me