493 hard to start when warm

Does it also run pretty hot on the hiway?

I had that one/two problem with my 367. (Hot-running plus hard hot-start).
In my case; It turned out to be too tight ring gaps, and/or tight skirts.
I tore the engine down, delivered the block back to the machineshop, where they honed the cylinders out another half a thou. Then I took it home, opened up the top gaps to .034, and the seconds a lil less . Then I put it all back together. That cured BOTH my issues. That was in winter of 2000; and she has run gangbusters ever since.
To be clear; my symptoms were like yours, PLUS running hot, that could not be cured in any of the conventional ways.
Sometimes when I shut it off, it would take 20 minutes for the engine to cool down enough that the Dakota starter could crank it over. Afterwards it was click/vroom-vroom, and off we go.
Oh and whereas before the change it was not happy idling less than 800/850 @14* Idle-Timing; whereas afterwards same combo would idle down to 500@5* Idle-Timing, and pull itself on hard flat even ground, with a manual trans.
and yes it had way more low-rpm power. I mean way more, lol.
It was a lotta work, but well worth it.
I was and still am running KB107s which are a hypereutectic piston.
The recommended skirt clearance from KB, for my 4.04bore was .0015 to .0020..
the machineshop originally set the clearance at .0030
I had it opened it up another .0005 or so