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GenIII maximum overbore?


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Does any one know how much a GenIII IRON block can be overbored before rendering the block unsafe?

 

How about Aluminum LS1 blocks? how much can they be overbored WITHOUT using new liners?

 

I am asking this to compare the overbore potential of genIII iron blocks vs aluminium blocks.

 

Thanks

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Per this article... http://www.automotiverebuilder.com/ar/eb040538.htm

 

Depends on the year..... "GM says you shouldn't bore the cylinders on the '97-'98 blocks more than .004? and recommends not boring the '99 and later ones more than .010?, because the iron liners are pretty thin to start with and they're serrated on the outside, too, so there's not very much material left to bore out. "

 

Definitive answer (along with 1000 opinions) could probably be found at LS1Tech.com

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I don't know what the maximum bore is, but iron blocks are routinely bored 0.30 over.

 

Everything I have read about the aluminum blocks says they can be HONED out < 0.010 inch like said above. Hardly seems like it would be worth the expense of new pistons.

 

Basically if you want a bigger bore on an aluminum block, then you either need new liners or just get a different block. And from what I have read new liners is a risky upgrade. Better to just get an LS2 block.

 

But LS blocks can be stroked easily. That seems to be the preferred route.

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