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Discussion Starter #1
I was reading in the July 2012 issue of "Super Chevy" magazine in their article "LS3 vs 418 stroker". They stated that in building their LSx stroker they couldn't use a iron block, LQ4/LQ9, because you are limited to only going to a 4.030" bore size!!!! What?!?!?So they went with the LS3 block with its 4.065" bore. !! I know that this is not true and I know we shouldn't believe everything that we see in magazines anyway.

But all the same I want to build my LSx stroker out of the OEM 6 liter iron block because I know that they are way stronger, cheaper and more plentful than the aluminum block (LS2 and LS3). I know that guys out there have bored these babies beyond 4.030".

A few years ago I know that at first 402 ci strokers(with the 4.00" bore) were all the rage then they were followed by the 408 ci (with the 4.030" bore). Remember those SLP short and long block packages? But there has got to be quite a few of those big bore big inch LSx strokers in the 415 ci to 417 ci range out there running around by now.

If you have one of these 415+ ci iron block babies withthe 4.00" stroke, please post your experiences here?? How big did bore out your iron block???
 

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My old Combo was a 4.060 Combo... Boosted.. 17-18psi for two years ... made 900+ The cam and valve springs limited me.... That old combo was bullet proof... over 200 dyno pulls and 200 track passes? ... Allways WOT but i kept good tabs on it. It allways had 155psi in all 8 and 55-60psi oil pressure at idle
 

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Discussion Starter #3
Thanks Casey for that vote of confidence in the iron block!! What I hear is for big cubes "iron bad!! aluminum good!!"

One thing I want know is why everyone or least alot of people are saying that for the OEM iron block the maximum bore 4.030" while they bore out the LS3/L92 block from 4.065" to 4.071"??? Why the 4.030" limit??? They both have 4.4" bore centers. The LQ4/LQ9 block is made of all cast iron and the LS3/L92 cylinder is made of soft aluminum and ductile iron. But it is safe to go with the bigger bore with the block that is made of the softer material and the the harder stuff is somehoe forbodden???

I don't get??

Please some explain why the "hard" limit 4.030" bore for the OEM LSx iron block???
 

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Maybe someone will chime with some thoughts like the L92 has more sleeve material, don't recall.

I had a 6.0 based stroker 10 years ago that was 4.060 bore. The popular thinking was that you had to pick the right block, some would not work. I do also recall folks doing 4.040 too.
 

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The one I'm building is a 416 based on a 6.0 iron block. 4" stroke with custom diamond pistons. Builder spent time selecting the right block. Should make good power and be reliable if the tune-up is good.

But LS3 blocks are good as well. Depending on what your goals are.
 

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I talked to Billyman about this about a year ago. He told me the trick to the larger 6.0 bore capabilities is proper block selection. Not all 6.0 blocks can go that large on the bore. Just gotta sonic test until you find one that can.

Aren't the L92's like 4.065" stock?

Mike
 

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Discussion Starter #7
I talked to Billyman about this about a year ago. He told me the trick to the larger 6.0 bore capabilities is proper block selection. Not all 6.0 blocks can go that large on the bore. Just gotta sonic test until you find one that can.

Aren't the L92's like 4.065" stock?

Mike
Yes they are, but I am trying to save some coin by going iron. I think it is like $1500.00 for a new bare L92/LS3 block. Compared to around $700.00 for a iron LQ. But the L92 has been out since 2007 in the Caddy Escalade and Chevy Silverado and GMC Denali. So some of them should be making their to the salvage yards by now.

Billyman is the man when it comes to advice and thinking a little of the box. Most of the speed and engine shops I've talked to stated that the 4.030" bore is considered the absolute "super safe" limit for the iron block. I assume that is without sonic testing and just machining the damn thing. And also there little to no difference in the HP and TQ numbers of a 408 ci stroker(4.030" bore) and a 414 to 418 ci stroker(4.060" bore) all other things being equal. So i might just settle on a 408 and call it a day.
 

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I'm building a stock crank forged rod and piston Lq4 right now. I have 4.060" Mahle pistons. Haven't fired it yet but I will report back with how it does on the spray.
 

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Theres other places in the build to find the 20ish horsepower those extra 8 or so ci would get you.

Your money,time and trouble would be better spent elsewhere. Buck up to the thought of the 408 and just go for it.

Make the right selections and you are talking about a 650-665fwhp pump gas motor.
 
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