You don't say what engine you have I am guessing it's something like a Pinto? If so I would be sticking with this as it's quite a good engine and very tunable.

The engines you mention are I4 (DOHC) they were also fitted to Galaxys (The early ones), they have moderate respect but again I would not have one over a Pinto personally.

Also if running one in standard FI guise you will need management loom etc, plus alot of other work.

Martin