With your single exhaust and 4 bbl carb on an otherwise stock motor,
I would not be bolting new heads on. maybe get a dual exhaust and some other wear parts for that money.
Fresh heads and old rings will just compound the next weakest link.
Soon you will be blowing oil out the tail pipe.

I just did the same on my 68 383.
However, I will be using HP manifolds and dual exhaust,
a carter 4 bbl I refreshed myself, and a new electronic distributor...
I have been collecting these parts for awhile.
I had one brunt exhaust valve and simply replaced that one valve.
I have not done any machine work as the motor ran and like you I am not ready for a rebuild just yet.
I did clean the piston tops and combustion chambers in the heads, with a wire brush then added a new cam, timing chain, oil pump, and gaskets.
The new stuff I got will most likely cost a lot less than the new heads and I still can use them when I get the long block rebuilt.

Obviously I'm not going to get tens of thousands of miles, but I will be enjoying it this summer and hopefully a couple more.