It's not oogie boogie. It's also not difficult.
You can swap 1973-80 warning lamp clusters for 1978-80 gauge clusters with some minimal work. Don't use the 73-77 clusters for this.
1973-75 gauge clusters have ammeters and capillary tube oil pressure gauges.
The ammeter was replaced with a Volt gauge in 1976.
The capillary tube gauge was superceded by an electric gauge in mid 1977.
The gauge fonts and colors changed in 1981.
The wiring from the engine bay will work for gauge senders or lamp switches.
The instrument panel plug will need to be re-pinned.
The temp and oil pressure switches will need to be replaced with gauge senders.
Pinout charts are in this thread.
http://67-72chevytrucks.com/vboard/s...d.php?t=456877
Year specific GM wiring diagrams are in the manuals thread in my signature.