I would buy the 72cc heads.
1) You can leave them as-is and try to run over 11:1 compression on your 400 stroker (461).
2) You can buy some dished pistons to achieve whatever compression ratio you're good with (I'd go for 10.25:1 max) and leave the 72cc chambers alone. The 72cc heads also give you the option of running them on a smaller 400 or 428, whereas the 87cc heads are really only good on a 455 or
maybe a 428.
3) You can send the heads to Dave at SD Performance (or buy the heads from Dave) and have him open up the 72cc chambers to a better-shaped 85cc chamber with his CNC machine. This may be the best way to go.
The 72cc heads have a better port shape than the 87cc E-heads mostly by virtue of the shallower 72cc chamber. This allows for a better short-turn radius in the ports, and the max flow numbers (270 vs. 280) are a bit better even when looking at the ones provided by Edelbrock.