Rudimentary valve clearance question.

I yanked my stock heads off my 383 yesterday and am replacing them with Edelbrocks 84cc head. I have zero deck and a single trough relief across the top of the piston 5cc. I am trying to find out my ultimate maximum valve clearance without buying a cam and installing it only to find I wasted my money. Of course I want the most lift I can get in there .600 would be great, duration and pattern I will leave to the cam engineers. I set #1 to tdc and rested the head on there without valve springs and pushed them in until they contacted the piston (they touch right in the trough) then I used a depth mic to see how much lift I got when I pulled them back up. Bad news .349intake and .372 ex. Does this make any sense? My old 516 heads were decked .010 and I was told by the machine shop I had .510 worth of clearance with them. I have been running a 484 cam but have been getting pump up at 5400 so I want a solid lifter double throw me down cam ( not triple since I only have 9.5:1). Any info?