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

Ok as the topic states, by putting 70cc closed chamber heads onto a basically stock piston 400 with the slugs .100" down the hole, flat tops with no valve reliefs, how much will I raise my compression? Saying the stock heads had around a 90cc chamber, and a .020 head gasket and around 8:1 compression, what would my compression be with a chamber that's 20cc less and say a .025 cometic gakset? Or .039 felpro gasket? I tried to do a compression calculator online but I don't know the dome height and all that of the stock pistons.

Now my second question how much lift can one get away with on a camshaft with no valve reliefs in the piston? Also around what duration and lsa is good for a hot street/strip 400? Heads flow around [email protected] lift. Holley 830cfm double pumper, 3300 stall, 3.91 rear gear, alum heads. Car has been lightened up a little.
What brand of cam would you prefer? I got a buddy that works at a parts store so I can get an off the shelf cam such as a comp, lunati, crane for about half price.
This is just a temporary engine until I get my 440 block redone. Or I may end up putting a 440 crank in this 400 after it goes, who knows. Haven't decided yet. Really just wanna get it back out there whooping some ford's and chevys soon. Lol I can think about all that other engine later lol.

Another question what kind of rpm can a low deck handle? Say cast crank, cast pistons, factory forged rods, arp main studs, oil pickup opened up to 1/2" soze, hugh volume pump, 6 or 7qt pan, (using the 7qt if it fits, if not I'm going to use my 6qt hemi pan) roller rockers, heads setup for external oiling. Some say they spin stock 383 and 400s to 6500, and even 7,000 and even higher, I honestly don't believe the part about 7,000 on a stock bottom end. In a way 6500 sounds fishy to me, I know when I had my cast crank 440 I was told not to go much above 6500 and I had kb pistons and a balance job on it.