high compression egge pistons for 273

I would use those hi-tops in a NY minute, and machine them to fit as may be required. It's really hard to get decent cylinder pressure in those small bores, for anything but a small solid-lifter cam, any other way.
Part of the problem, you're gonna find out real quick, is getting a decent headgasket.
Nobody makes the special 273 gaskets anymore, and what you can get instantly drops the compression ratio quite a bit.
IMO, those hi-tops are Gold, just fit them very carefully.
Another problem that you might encounter, is keeping a composition headgasket in them. The cure is very flat decks and heads, with a slightly rougher than usual surfacing.. and retorquing after break-in................... This ain't your grampa's lo-compression 318.
If you will be running an automatic and hi-way gears, I highly recommend a solid-lifter factory type cam, and a tight squish, just to keep the cylinder pressure up. There is a pretty good debate on how little squish you can run; which is gonna depend a lil on which rods you are planning to use. I'll leave that to other smarter-than-me-guys to talk about. But I can tell you that my 367 has the heavier 318 bushed rods in it, and those I have run to 7200 under alloy heads for years (decades actually) without contact, with as little as .028 clearance.
Before you bolt the heads on, be sure you measure everything, calculate your exact compression ratio. Then, when you have retorqued your heads, and checked your valve lash, do a compression test. The results of the test will point to what fuel you may have to run when at WOT, to avoid detonation.
Happy hot-rodding