I am in the process of remodling my shower stall. I need to change the shower drain from cast iron to ABS. What do I need to do to complete this project. Can I splice the two together?

Thanks

Yes you can splice into cast iron, there are neoprene gaskets that will do the job of connecting the ends together. One is called "Fernco Adapters" and another one is called "No Hub Adapters". The biggest job is cutting the cast iron, you can use an electric jab saw, it may take you a couple of blades on each cut. The pipe is not the bad part to cut but the rust inside of the pipe will dull the blade very fast.

I don't recommend Fernco Neoprene Couplings unless there's a compelling reason to do so. The reason being is that they aren't ridged. Unless braced they can sag and bell presenting a potential drainage problem. I prefer NO-Hub Couplings, (see image). They support the pipe.
Cast iron is brittle and very hard to cut with a Saws-All. While it can be done with time, patience and a bunch of new blades a much easier way would be to rent a set of cast iron ratchet or snap cutters. Good luck, Tom