How much will 70cc heads raise my compression? Also how much lift?

Yeah bores are perfect, no ridge, and the mich checks everything good and the crank and all looks like they did a balance job on it. It's still stock bore size I'm thinking it was a low mileage rv motor and they did somewhat of a build to it they had a 7qt milodon oil pan, tapped the oil pickup to 1/2" hemi size, .509 purple shaft cam, Holley street dominator intake, 906 heads that had been shaved a good bit. The Pistons appear to be forged from what I could tell looking at them with the oil pan off...