http://www.fullsizechevy.com/forum/g...es-w-tach.html
here is one writeup about installing 92-94 gauges in a 88-91. do some searching, there are a few.
my article was about swapping a 91 (only) tach cluster in a 88-90. 88-91 did not have a separate DRAC, it was incorporated into the cluster. 92-94 the DRAC was separate.
my write up was different because i was swapping a 91 (only year with a tach and internal drac) into a 88-90