Using a 92 4.3L and 700 transmission

Has anyone used a later model TBI engine with electronic ignition with the electronic lockup transmission in an earlier model car. I am planning on using a wrecked 1992 Astro donor car to supply a repower to my 1972 Triumph TR-6, and am curious what kind of electrical issues that I am going to run into. I am planning on using the ECM and wiring harness from he Astro, but I am considering using an aftermarket hot rod wiring kit for this job. Any input would be appreciated. I also am going to have to find some after market gauges, including speedometer that will work with the newer electronics. Any recommendations? Thanks in advance.