Where can I buy a propane system for a 1978 Chevy pickup in the Metro Mess?

I would check with Ferrell Gas or a local propane distributor first.
There is a company in Red Oak on I45 called Knap Hide that builds utility beds and outfits trucks that puts them on some of theirs.
Be prepared, new systems run upwards of 7 grand or more.
A system for an older carbed vehichile without all of the computer controlled systems should be cheaper. If you can find one.
Good Luck!

Years ago I worked for a mechanical contractor and all of the vehicles were equiped with propane systems. These guys have been in business for years and did all of the service on the vehicles we used back in the day.

http://www.northwestpropane.com/

hank hill with strickland propane, arlen tx.