Ok you can use a B16 head with no problems. IMO save your money and get a B16 head and then port it.
Now in terms of opening the chamber in the B16 head or any VTEC head for a ls the is no need. All b-Series blocks (except for the B20) are bore to 81mm, and the head will match that no problem.
Head bolts use GSR/Type R head studs since the block height is taller than the B16 block.