I wouldn't sweat the quench at all, .055 - .040 IMHO is decent quench.
What is bad quench? Some engines are deep enough you can measure with a ruler, heck my truck 390 was .130 in the hole, .170 when you added the gasket!
If I remember correctly you went with a pretty mild cam because you didn't intend to spin it too high, if DCR is bothering you, crank the cam forward 2 degrees, it'll probably offset what you lost with the deck and maybe even be happier down low.
As far as porting, an old saying we had was "you make power with head work"
I think a good set of viton seals, aftermarket CJ valves and porting would be certainly noticeable, the question is how much do you pay? Les Schmader in PA is pretty affordable, as is a local guy here in NE, but if your guy charges a lot, it comes down to what you think 25-30 hp is worth.
Make sure you know what you are getting though. Cleaning up the ports wont do much, cleaning up the guide area and a good transition to a modern valve job will, especially if combined with some work on the ports.
FWIW I have about 800 bucks in my iron heads on my new 445, new springs, guides, valves, full port flowing 277 cfm. That is with shipping from Nebraska to PA and back. It's in a 4x4 with a 270H cam.
Keep in mind an FE also is sensitive to intake choice too, so if you port the heads to flow 280 cfm then cap it with an SP2P, it's a waste, but a good matching intake it gets better and better
Ultimately though, if you are only going to run it part throttle idle to 3500 RPM, I'd might give up the power potential, but if that 10K has you rowing gears now and then, I think you'd be happy if you shopped smartly.