I'll follow along. I only have used the old Stealth heads on the 1969 Coronet 505" stroker engine,
I bought those along time ago, so I have no idea how they compare to the current castings?
My castings were nice quality, but I never run heads out of the box. Needed to change springs and retainers for the hydraulic roller cam, so also did some mild porting and valve job while they were apart.
Didn't need to surface my heads?

Originally, I wanted to use them for the more stock look, with manifolds, but I kept making changes to the engine with headers, EFI and such, so now the "original" look is a non-factor, and I though about going with a head with better spark plug placement (in the chamber.)

I haven't used the Edelbrock E-Street heads, but they look decent on paper, and have a slightly smaller chamber volume for more compression.

The aluminum heads use reduced wrenching head bolts, so figure the bolt hardware into the cost of the aluminum heads.

The 915's could be re-built at less cost, and you could re-use the original head bolts. For the $1,000 cost of the aluminum heads, you could put the larger stainless valves in, and hardened exhaust seats in the 915's, and maybe even some mild porting?

Anyhow, if you want more originality or lower cost, I would likely rebuild the 915's with the larger valves and some porting.

If you want performance, the aluminum heads might be a better starting point?