Been searching around on this forum and LS1Tech...

My primary goal is durability for my mostly street driven C5
I purchased the car last year from a member/former sponsor/friend. He set the car up with an A&A Vortech YSi, ECSMeth, Innovators West 8 Rib, ARH,
and a bunch of other supporting mods hanging on a stock LS6...Vette Doctors did a great job on the installation...

I am at 600rwhp at ~8#...the car is a blast to drive, the boost hits hard but high. Low rpm is a little soft... It has a safe tune and would probably be fine for years.

Initially I was thinking pump gas, budget oriented LS6/2/3..stronger rods and pistons, lower static CR, stock crank, pulley, tune and have some fun.
That lead into including a forged crank may be worth the piece of mind....plus displacement choices.

Somehow(?) I found myself on the ERL and RHS sites as well as looking at LSx iron....I like the ERL packages, but not having a core to send will drive the price up a bit more

LSx seems like a great deal...cost effective, stout, lots of cubes, better oiling, 6 bolt head pattern, but with a weight and heat penalty.
I would like to do some roadracing down the line. Iron is probably not the best choice for this activity.....

I'd like to pulley down to around 15#, and have more available torque in the lower rev range..

Please let me know what block/rotating assembly you are running on your FI setup...Opinions on LSX?

I plan on gathering parts this fall for the build.
Anyway, just wanted to get some feedback...

Thanks guys..

 

I'm in for this one.
I have been looking at the LSA or LS9 blocks, kind of expensive but light and strong.

 

Kinda forgot about these..where do they come in price-wise?
How much extra material over a standard LS3?

I keep coming back to the LSX block. If it was any other car, I would call it a day...

I have seen some estimations, but anyone know how much heavier is is than a stock a typical aluminum gen 3 or 4?

Could a good coilover offset the extra weight?

 

go either with a rhs block or erl set up and never look back than u dont have to worry about the extra weight!!!!!!!!!!!!!!!!!!!

 

I am in the same boat........

 

Make sure the LSX block doesn't have a core shift. Personally you don't need that block unless you are going to make big big power. I'm making around 800 on a 346 block. I would go with a LS2 or LS3 block and stroke it.

 

I hear ya...this was my original plan...
On one hand I would love to be in the 8 range and still have a bank account....

...and on the other hand I am trying to do may part by helping the economy

Both RHS and ERL these are really nice solutions..6 bolt heads are a nice option..and I agree re extra weight of the iron lsx being a deterrent.

This is sexy:
http://forums.corvetteforum.com/c5-t...lxr-heads.html



What are you leaning towards?

 

If/when I build a motor, I can't decide on a LQ4/9 or LS2/3 block. I already have the extra weight of twin turbos up frot with cast manifolds so idk if Id want to add the iron block to it.

 

If I had the money I would have gone erl but I didn't so im having the ls6 redone and stroked to a 383. It should be fine with my a&a kit but im only running an si head unit so Ill probably max out at around 11 lbs and maybe 600-650 whp. Ill let you know how it is though.

 

LSA $2537
LS9 $3807

From Scoggin Dickey

Not sure about weight, but have to be a lot less than any iron block.

I think the LSX block is around 100lbs or so more.

 

15psi of boost....600 or 800 hp???? unless you just want a aftermarket block just to say you have one, you don't need it.. these are very low numbers

And all this talk about a iron block is heavy is code for "i don't make enough for it to matter". When you start making big power, you will only go to a iron block, plain and simple.

 

I'm making 800 on a small block. You don't need iron unless you are going to run big boost. You don't need 6 bolt heads unless you are going even bigger.

 

At 600-800hp and 15psi boost, any of the blocks mentioned will work. It all depends on your wallet and goals. If weight is not an issue and you plan on stepping it up in the future go with the cost effective LSX. The RHS/ERL are way overkill. The LS2/LS3 blocks will easily handle your power level.

 

In fact at that level the LS6 block is fine.

 

Did some more digging this weekend on the topic..
Seems like the 1000/15# is a crossover point.
Part of my thought process was to over-engineer to allow room for growth. Not looking to throw money away, but looking to build a strong base.


Kinda funny how 6-8 is considered low!
A few years ago, LS1 folks were trying to break that 500rwhp barrier


Seriously leaning towards forged LS6/3 and calling it a day.
The price of admission with the aftermarket blocks are really steep, and I agree with the overkill comment as far as spendling big money on moderate hp levels

I can see how 100+ lbs of iron block would get lost if you are making big numbers.
I was more curious about the handling differences resulting from the extra weight



Thanks for the LSA/9 feedback. I assume they should come in pretty light.
Looks like the dofferences between A and 9 are deck plate honing and steel mains...
Wonder what the differences between A and 3 are...


Thanks for all the feedback so far!

 

It's been my understanding for a while that the iron block only weighs 85lbs more.

 

I keep seeing estimations around the 100 mark...
That would bring an otherwise stock Z06 up to C5 weight

Plus with the motor sitting behind the front wheel line....I cant see it having a dramatic effect on handling.
Not much more cash than a 3..... plus room to grow

 

cost effective way-
use the stock block and crank
forged rods and pistons
and call it a day, thats what i did and im around 900 rwhp

 

Been following your build(s)! Bookmarked it a while ago
Around 900 is awesome!
I know the stock cranks are very capable..

 

The stock crank is good to at least 1000 flywheel. Probably good to 1200 but I'd go forged for that.