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

I remember reading a while back where these guys took a motor home 440, put on a good set of ported 516 heads, 509 cam, intake and headers, and played around with different parts and made close to 500 hp without going above 8:1 compression, said the compression could've been more but they did a lot of valve deshrouding so I'm hoping with only 40 less cubes and a better head and maybe a better cam I'm hoping I'll get at least 450 and its also going to be a lot lighter than an iron head 440, stock vs stock I think the 400 is what like 40lbs less, then the alum heads will take off another 40 also the 400s ability to spin more rpm and shorter stroke, lighter rod, crank, and piston, I guess we'll see, and if she's still a little slow I do have 2 sets of solenoids, maybe put a 75 shot on it lol