best compression ratio street build?

stock bottom end and some kb107 pistons mated with cleaned up iron 360 heads will get you the 300 or more your looking for. Of course a good dual plane intake and a 4 barrel carb are a must. I think with standard 360 heads not milled you would be right around 9.7 cr. Then there is the exhaust to think about to.....then you need to figure out cam size, tire size, gear ratio, manual or auto tranny, converter......as far as gas mileage I would throw that out the window. You could just buy a 500 dollar 4cyl beater for that.