b18c1,b18c5,b18c3/b18c6/b16b = the same exact casting

b16a/b17a = the same casting

The crank on the b16b has the same dimensions has the b16a but has the smaller width rod jounrals like the gsr and ITR and it is counterweighted better for stability at high RPM. The b16b has a very long rod to make u[p the remainder of the deck height and the piston has a compression height of 1.210" versus most other b-series which are around 1.180". The rod ratio of the b16b is over 1.8:1 I believe.

Now to your situation. Pick up a 1.8L crank and matching rod set. For rods only run aftermarket if you are running forged pistons. if you run an ls crank in your block it would be a good idea to run forged pistons so you could delete the oil squirters since it is a bit harder to get them to fit with the 89mm crank.
If you ran a gsr/ITR crank with gsr rods and your stock pistons the compression will be around 12.3:1 or a little higher, which depending on how you plan to tune may be a bit too high.