Conversion of Gas to Diesel

[69MyWay]

I am curious. What did GM do 25 years ago to convert gas engines to run on diesel?

Can a Chevy 454 be converted for minimal cost and junk yard swap parts?

I know there were issues with them and GM actually offered to replace the diesel with gas engines for many customers.

How cool would it be to convert, then get it to run off bio-diesel brewed in your own garage?

My initial guess is the compression ratio has to go up. Spark plugs go out and get replaced with glow-plugs. Distributor cap gets capped off.

What else?