It would all depend on wich crate engine? Any where from 270hp up to about 425hp. And most 350 blocks will not go to .60 over bore safely! You will tend to run into thin cylnder walls etc. Why do you want such a large over bore? I would say that you might gain 3 or 5% with an over bore. Just my 2c's.
oh ok, well these are just the specs the guy i bought it from told me, so i was just wonderin about how much horse i gots.
weather its safe or not is beyond me, but he just told me it was a 350 bored .60.
'78 K10, '73 blazer frame with shortened bed, 355/400/205, 1-tons, interior cage, 8" suspension, 40" swampers, true duals, fiberglass cowl hood, built for killing
Just to clarify, I have to assume you mean 0.060" (60 thousands), not 0.60" (over half inch).
The purpose of boring an engine that amount is NOT to make additional power, rather to simply clean up the ridges, scrapes, scores, etc.. in the cylinder bores caused by wear when you rebuild it. The 0.060" overbore gives you about an extra 7 cubic inches of displacement, or a whopping 2% increase in displacement. Assuming all else is equal then you could also expect an 2% increase in horsepower (i.e. you wouldn't notice the difference).
An 0.060" over 350 may be worth even less money because that basically means you have to throw the block away if it ever needed another rebuild because you can't bore it out anymore.