TA63

iTrader: (5)

If I was to put together a turbo build targeting 800-1000 hp or so, should I be using an iron LQ4 block or an aluminum LS2 or LS3 block? I'd like the weight savings of aluminum, but cant afford a catastrophic failure.

boostedxs

An l33 could do that safely all day.

boostedxs

of course, if your wallets deep you could get an even stronger aluminum block. I suggested l33 bc their relatively easy to find, fairly cheap, and can hold 800 hp with absolutely no problem. just my 02. I'm sure some others will chime in here shortly with some other good options. that's just the block I have actual experience with

oscs

iTrader: (19)

Stock 6.0 is my choice

stevieturbo

If you have a catastrophic failure at that level...it wont be the fault of any of those blocks.

LS6427

iTrader: (2)

You can loose your entire aluminum block just by having the starter break the mounting tab, which actually happens a lot. Stripping bolts happens too. I stripped my A/C pulley bolt and it was a bitch to have it tapped and an insert installed to make it work again.

Why not just get an LQ9 iron and be much stronger than any aluminum block. The weight difference is meaningless in every way...unless you are a competetion drag car looking for every tenth of a second and already are doing massive weight reduction.

When I went from aluminum to my now iron 390ci...there was zero difference in the height the front end went down....I measured it. It never moved. The feel when driving aggressively is 100% identical in every way. And if you going 800-1000 HP you're gonna be going WOT in a straight line so the extra weight means absolutely nothing......NOTHING.

I rather have the piece of mind of iron. And you can find an LQ9 block for $400. Why deal with sleeves and aluminum.....?

Not sure how much cash you have...but if/when my current LQ9 block has any problem or failures of any kind internally or I need to upgrade to 6 bolts per cylinder for more power.....I'm getting an LSx iron block and then I will have Darton sleeves installed into it. Thats the ultimate in block strength.

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stevieturbo

Weight will affect everything, cornering ability, braking performance, acceleration etc etc.

It's silly to say it wont affect the car. For drag racing only the effects may be less, but extra weight is still extra weight, and if that weights serves no real benefit, then it's just silly having it there.

Obviously the heavier the car is overall...as a percentage the extra weight may affect it less, but if the car is lighter then the extra weight will be worse

If you're stripping threads it isnt the blocks fault, it's the person screwing stuff...or trying to screw stuff into the block.

Ive seen people mention about breaking the block in the starter area...not sure how it's happening though

LS6427

iTrader: (2)

Thats why I mentioned unless its a purpose built car for some kind of serious use.

My car is a 100% street car...the extra weight up front has zero effect of any kind. I drive it aggressively and there's absolutely no difference of any kind.

I'm sure a road race car or a drag car will see some differences, but then the road race car will also have many upgrades to the suspension and the drag car will have more power to overcome the approximate 100 pounds extra weight, which equates to about 1/10 of a second in a drag car.

The A/C belt tensioner pulley bolt just started making noise...it was coming loose all on its own. The dealer tightened the bolt and it was fine for about a year. Then it got loose again. The guy tapped it and inserted a steel sleeve. It held for the next 8 years no problem. But that wouldn't happen with an iron block. Many things are just better and stronger with an iron block.

If the OP is building a street car....the extra weight will mean absolutely nothing and he won't feel anything different. If hes doing purpose built racing...he might want to think about the extra 100 pounds.

But if hes doing what I'm doing...straight line highway roll racing....I'd go iron all day long for the extra strength.

Aluminum = less strength, more things that can go wrong, more expensive.

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stevieturbo

Alloy blocks are plenty strong for 1000hp, and then some.

LS6427

iTrader: (2)

No doubt....but iron is good for 3,000+.......

A 1000+ HP aluminum is hovering around its limits though. Internals being all equal.....comparing an aluminum 1000 HP engine and my iron LQ9 iron engine, my iron will have MUCH more strength and reliability. I went iron because I wanted to be far away from by block limits at 1000 hp.

The other aftermarket badass aluminum blocks like Dart and Warhawk are obviously stronger than the regular LSx aluminum series, but now you're talking many times more on the cost. And then still, an iron block is FAR FAR superior in strength and reliability to all of those expensive aftermarket aluminum blocks.

But I agree with you, for about 1000 HP the aluminum will be fine if built by someone reputable and tuned by a very good tuner. No room for error at those power levels.

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