Mahdi

Hi
I wanna know whether a 6.0 iron block with .040 over holds up fine with about 16lbs of boost to make 1000 flywheel horsepower or not?
By the way, it will be an offroad race truck.

C5 Pete

Mahdi

Thanks for your response
That 40 over is for clearing the cracks.
I don't have problem with pistons, maybe a set of forged sbc ones with some customizations!
I've seen guys running stock block in same hp range for years with turbos but with .030 over. But everybody says it's max overboring for FI engine.
I was curious to know if that 0.005! less wall thickness makes problem or no! 😅

BLOWNBLUEZ06@RKT Performance

One block might be okay and another not so much. You can find a shop with a sonic tester to verify thicknesses on all of the cylinders. Cap'n Huff mentioned, filling the block with a bit of concrete and should help stabilize the cylinders even more and increase your guarantee of things staying together. I can't say that I would recommend running SBC pistons in an LS engine. There are far too many differences to even bother. I can have you a set of custom pistons made if you're interested. I would recommend doing that with a nice set of rings along with a set of tool steel wrist pins so that they hold up to the abuse better. Let me know if I can help.

Bret

Mahdi

Thanks bret for sharing your knowledge
How much wall thickness do you recommend for less than 20lbs of boost and not much of compression ratio on that block?
And what about putting new dry sleeves in it? Would it increase the strength?
For the pistons, as sbc pistons share same dimensions with ls ones (I think the main difference is just in ring widths) I thought they can be used and actually I've seen some ls motors with them, but what am I missing?
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BLOWNBLUEZ06@RKT Performance

The skirts are deeper with SBC pistons, the valve reliefs aren't in the same place. I know that the wrist pins are offset in a lot of LS piston designs. The way I see it, there are things that people have gotten away with that might not be such a wise choice. There are many different places to measure thicknesses. I would prefer to see a minimum of .200 where the thrust lies. It's cheaper to start with a fresh, un-bored, used block than start sleeving one that's over bored.

C5 Pete