songfta

I already looked at the following forums thread:

https://bikeforums.net/showthread.php?t=172580

But I didn't really see a good answer for this question. So...

I have an Easton EC70 (carbon steerer, totally unused and uncut) that I'd like to use on a new frame. The frame I'm considering has an integrated headset setup. Is it feasible to use the fork I already have on the integrated frameset, or should I get an integrated-ready fork with the new frame?

I'm not really worried about aesthetics - function is my concern.

roadfix

In that case, the answer is yes.

I use an integrated fork with a conventional headtube. This is not an uncommon setup. Conventional head tubed frames are sometimes sold with integrated forks. They match perfectly.
But you are looking to do just the opposite. Your setup will look fugly, but functional.

songfta

That's what I needed to know - thanks!

Any long-term concerns in terms of bearing maintenance, beyond the usual preventive stuff?

HillRider

Nope. All the Integrated and Zero Stack headsets I'm familiar with use cartridge bearings which are even more maintenance-free than the older loose-ball type. I pack a lot of grease into them just to keep out water and dirt and overhaul and regrease them every year or so.