Been away from this party for a while....OP, I would consider the 60779 Edelbrocks as an investment for the future. Your'e going to lose no more than .25 point of compression going to those over the present 273 heads, which are likely around 60 cc's in chamber volume. (57.3 cc is the NHRA blueprint spec, and is small than typical factory head volume.) AND, if the prior rebuild used standard Felpro 8553PT head gaskets, then the CR is going to INCREASE over what you have if you use the Edelbrocks and a thinner .028" head gasket (Mr Gasket PN 1121G).
302's are a cheap alternative but have around the same chamber volume as the Edelbrock's, so there is no compression advantage there. They are a cost advantage now, but will be a long term HP dis-advantage due to less breathing by far than the Edelbrocks. But, that depends on how far you want to go long term..... the 302's might be fine for your intended use.
So, IMHO, IF you have the coin to spend, and want to look long term towards more torque/HP, then I'd say slap the Edelbrocks on with the thin head gaskets, put in a mild cam and new chain, and go. As suggested, you can go back later and replace pistons. OR, maybe better yet, build another short block (318, 340, 360) and do it up right for how you want to use the car and build it around transferring those Edelbrocks onto the new short block. They are known good pieces for 400+ HP OOTB, when supported with good intake and exhaust breathing.