And what car do they most commonly come in??
Yep yep i'm looking at a LT1 rebuild in a year but in foresight i'm thinkin a swap instead. It's time to step on up to the latest.

 

Iron blocks are truck motors. The 5.3L and the 6.0L

Bret

 

Lq4 + Lq9 right?

All gen 3 top ends are compatible with BOTH?

 

Yes and yes.

 

Do they come stock with iron or aluminum heads? I've noticed their manifolds are different, why ? Which manifolds are better the truck or passenger car ones? Will the stock truck bolt on, on top of lets say LS1 or LS6 heads? what are the drawbacks?

 

Early 1999-2000 LQ4s had Iron heads, later 2001+ LQ4 and LQ9 had the 319 Aluminum heads. Trucks have long intake runner manifolds to help produce low end torque, the LS1/6 manifolds do not need to produce low end torque because they are used on lighter (than trucks towing cargo) passenger vehicles. Truck manifolds peak at around 5000 rpms, where as the LS6 can go upto 6800, but the LS1 can only go upto 6200. Both will interchange, as will all the other engine parts. If you are considering an Iron LSx swap, consider the LQ4/9, these engine came in Silverados/Sierras/Vans (1500HD and 2500), Escalades and Denalis.

 

 

Hoes yes I am seriously considering and even though it is a year away if not more I like to do my research early while I look around for the package and it's prices, I think it is awesome that we can get an Lq9 and bore it out later of need be or run some serious nitrous through it, for me iron is where its at, and seeing as to how well populated the Lq9 sits in all those cars it makes even more attractive.
A last question and if you don't know it's not that important, can I with a different bellhousing (I imagine at minimum) bolt on my T56 to the appropriate bellhousing? or are the newer bellhousings matched only to what could be a newer casting or boltup pattern on later T56's? rendering my older t56 completely useless.

 

Kinda curious but why iron?

 

Strength

 

For what? They gonna be using it as a bowling ball???

The aluminium block has been proven at well over 1000rwhp, how much power are they planning on running?

 

And they've grenaded at a lot less than that too, what's your point.

I see a lot more Alum blocks with holes in them then I do the Iron ones. Care to explain...

 

Well firstly you need to establish what was the cause of the failure. If a cast iron block would have still failed under the same circumstances then it proves absolutly nothing.

BTW - I'm not actively disagreeing I'm just want to see if this "opinion" is based on something more substantial than outdated heresay.

Also race/drag, vehicles which run a Gen 3 SBC, i.e. LS1 are more likely to be Corvettes and Fbody's. I know there are lots of trucks out there with LQ's but seriously how many are used as a performance vehicle?

So following this logic how many 98-02 Fbody's and 97-04 Corvettes run a cast iron block from the factory?

Well noone is the answer, so logically speaking the ratio of aluminium engined cars compared to cast iron engined cars is much greater. So you should see more failures from aluminium engined cars.

Example:

Lets for arguments sake say that 1 in 10 aluminum engines fail and that 1 in every 10 cast iron engines fail also.

However there are 4 times the number of aluminium engines compared to cast iron.

This would mean you should see FOUR times the number of failures from aluminium engines. However it would have nothing to do with the material itself just the popularity.

As I say I'm not disagreeing it with you just trying to look at the bigger picture. Also there are many many many people making quite extreme levels of HP perfectly safley (as far as the blocks concerned) with aluminium blocks.

 

Those stats as you used them are purely hypothetical, and I would tend to think that here in the US there are in fact alot more trucks being sold than all the sports cars put together. Not that I don't understand what your example means.

Your also putting aside the old school type rebuild which can sometimes be pulled off by joe average in his backyard without requireing new sleeves.

Although it may seem like the aluminum stuff is gods gift to us chevy buffs, sometimes things aren't what the general popularity says it is. I'm sure the 1000hp guys spent a lot of time, massaging and balancing, and blueprinting and tweaking internals, sonic testing, chamfering, deburring, and yada yada yada, my pockets don't run that deep.

I need the sureshot, and with minimal hassle, I can drop in a forged crank+pistons, balance the assembly and feel fairly confident that with the right tune she'll survive some heavy N20 doses with most to all other parts close to stock and no rigging the oil system or testing for hot spots, fancy equipment or sleeves to worry about should there be a failure.
And last but not least I like the new school stuff but I still have a lot of the old school in my blood, so keeping an open mind to the newer stuff doesn't mean I want to just follow, I thank Gm for the design improvement and I thank them twice for the available iron alternative that fits my line of preferences.

As for the weight differences, I'll take it's slight to null penalty, anytime, knowing that a hole on my piston skirt is less likely to happen to me. And I also thank the crowd that underdogs the iron block, cuz if not for them the costs would actually be higher than the aluminum, heheh, so it's a win win all around. For me that concesus works to my benefit so it tends to paint a smile on my face and I laugh cuz it's a beautiful thing when you really look at it.

 

= Lq13....

 

 

Cool although aluminium is as much "old School" as cast iron. The Rover V8 aka Buick 215 was designed in the 50's as was the Aston DOHC V8, Jagaur V12 and they all had aluminium blocks and have all been proven to be reliable race engines with the block never being an issue.

 

They have the same bellhousing shape and matching (well, 5 bolt holes) pattern as the SBC/BBC. So you are good to go. I would recommend an LS1 T56, this will vastly simplify the installment.

 

there you go again bringing up cars that we never hear talked about.

 

just a FYI, I rebuilt a pair of 6 liter heads out of a 2500 truck a week ago that were cast.