aAZz

I have a 5.3 that I'm thinkin of boring out 2 ls1 specs. I can also get a ls1 block for cheap tho my concern isn't weight its reliability. So my question is what would be more reliable in the long run wit nitrous on stock bottom end wit a big cam?

King Nothing

iTrader: (9)

The iron will last longer, the aluminum will work but the iron will last from the right builder

aAZz

Yea that's wat I've been thinkin. I want the ls1 but I kno its a lot weaker than if I build the 5.3 to a 5.7. I already have the pistons and crank. New cam, lifters, and the 5.3 heads. So I might just bore this out to a 5.7 and keep the iron block

aAZz

Block is in great conditions

PREDATOR-Z

The one that is properly built & tuned will last longest.

aAZz

Like I said the bottom end will be pretty stock other than being bored out. It'll have stock ls1 pistons and stock 5.3 crank. I'm lookin for around 430rwhp wit my cam on motor

nobreaks254

iTrader: (50)

I built a iron ls1 for my 92 Camaro. I think is it a great alternative.

aAZz

Really any pics? Videos? How did it perform power wise compared 2 a ls1? Dyno numbers?

nobreaks254

iTrader: (50)

I have pics somewhere but I have since sold the car and bought a C5 Corvette. There really shouldnt be any difference in power to a ls1 if built the same. Mine had ported 799's and a small 216/224 cam. I never got it dynoed but there are afew Mustangs that think its pretty fast

aAZz

I've been doin research but can't seem 2 find anythin

Bilster

iTrader: (21)

There are a number of factors to consider. Not really answering your question but here are some things to think about.
Generally speaking, every 1000 pounds removed from a vehicle is like 100 to 150 horsepower, depending on where you get your information. The LS1 will be 100 lbs lighter than the iron 5.7 so it makes sense there is some horsepower to be made with the LS1 in terms of weight saving.

On the flip side, the best bore that a machine shop can provide is a torque plate hone. With the amount of material you need to remove from the 5.3 block to make a 5.7, you will absolutely be able to torque plate hone to a near perfect bore. With the LS1, it's a crap shoot. There is enough movement when dealing with alum. blocks that you may not be able to torque plate hone with the material you have. That is going from 3.89" standard bore to the maximum 3.906. I bring this up because if you are building for durability, a perfect bore has to be a consideration.

KCS

iTrader: (20)

I've had to hunt for aluminum 5.7L blocks several times now, and I've wasted several trips only to find cracked blocks. I would prefer the iron block, unless you have one lined up that you know is good.

aAZz

That's why I'm leaning towards the iron block for the factors that u both mentioned. I'm sure performance wise they're really close 2 comparison am I correct? And yes I agree a real lsx block is great and reliable but I don't want 2 later down the road have a cracked block or have 2 change it out due 2 wear

revtech101

^How do you crack a block due to wear? I hate to say it but you may have been il advised.

I strongly agree with PREDATOR-Z

Leaving bad machine work and assembly aside, if you tune your motor poorly, it wouldn't matter what it is made of, built or not built, billett, forge or cast, it will blow like the 4th of july.

Conclusion: Use the Aluminum block by all means simply due to weight advantage and better overall balance of the car.

aAZz

Well goin 2 see the block tomorro u guys think my block plus 130 is a good deal? That's pretty much what it would cost me 2 bore it out so price wise its pretty much identical

KCS

iTrader: (20)

It doesn't take much pregnition or detonation to crack the sleeves in an LS1 block. With an iron block, however, you would almost have to try to run 87 octane with 30psi of boost to crack the block.

The iron block is simply more forgiving if you trust your engine to the wrong tuner.

PREDATOR-Z

When it detonates, it is not the sleeves that cracks first, it is the piston ringlands or just the rod that shatters.
Anyways, how much nitrous are you going to push through, I've pushed 250 wet on a regular basis (forged assembly) with no issues, Tune, plug choice etc... is of outmost importance once you go over 150 shot.

aAZz

Biggest shot would be 150 but plannin on just 100 shot

KCS

iTrader: (20)

Not always. I've already seen first hand an LS1 block with a cracked OEM piston and a cracked sleeve, each in different cylinders. At least with iron, you stand a better chance of salvaging the block.

redbird555

iTrader: (14)

Agreed iron is more forgiving but there are hundreds of cars on the site running a 100 shot with a decent H/C setup on stock blocks as long as there is a good tune there should be no issue. Hell with a bad tune both blocks stand a chance of becoming scrap metal. I personally dont see the need for an iron block unless you are running a crazy amount of boost or hp. Aluminum works jsut fine in all of our cars even pushing 500whp so ya I vote aluminum , plus it kkeeps weight down..