'77 to '80 Gauge swap

[yodert]

Just grabbed a cluster out of a '77 Scottsdale with the tach and the smaller gas gauge. My '80 Scottsdale doesn't have a stock tach, so I wanted to swap all the gauges from the '77 housing to my '80 housing so they all match. I understand the '77s oil pressure gauge is mechanical, and the '80s is electric. Is this swap do-able? Can I run the mechanical oil pressure gauge in my '80? Also, my truck doesn't have a stock tach, and was hoping GM pre-wired for tach??? (I know, long-shot question) If not, what type of customizing must I do to make it work?

Thanks!