Well I finaly got some info . And I'm still working on details.
LPG tank so far is a PITA . Casue it needs to be US DOT apruved all that happy hourse shit

. The electronics and control valve end is taken care off. It will ruffly cost about $700 , and then the tank or tanks will be additional ~ $300. So now I'm stuck on the tanks.
Anyone has any good ideas where to stick a tank or tanks under that thing ?
Cause 44" x 8" cilinder is really tiny . it dose not hold that much . But I have to do more reasurch . Casue I know that they run tanks that go into the trunk where spare tire was .
And LR needs to use liqwid , casue Compresed is only like 87 octane , when Liqwid is like 97 or 95 octane.