I did a search and found several threads that deal with related issues, but none that answer my question directly.

I am looking at a B20 block for sale that is bored to 85mm and having a block guard welded in. I suspect this is too far to go on stock sleeves, but wanted to see what the rest of you had to say; particularly those with direct experience. I would use it for a boosted daily driver, probably 300 - 340 whp.

Tell me what I need to know.

 

With out any detonation you may get away with it.But after searching I'm sure you know this.Hp is not the cause.If it was me I would just run a b18 until I could afford a sleeved block.B20 is kind of a waste of money for turbo.A b18 will make 300-340 hp reliably.Not saying it can't be done with a b20.
Glenn

 

That's pretty much what I was thinking after reading the archived threads. Anyone out there ever actually boost on a bored B20?

 

a friend of mine boosted a stock b20b and crack #2 and #3 sleeves on 12psi, tuned with hondata. it lasted him 3 months and he was beating on it everyday. so i would rather stay away from a bored out b20 and go with a b18.