That has got to be murder to completely strip out,,clean,, prep the metal and redo,,, all without doing any damage to the outside paint job while using all those powerful chemicals.
I was looking at one companies liner kit. It had to be a 6 step process.
Aye it is a bit of a pest of a job care has to be taken that the tank is properly liquid tight before carefully pouting i the various chemicals and sloshing them around
i used some old inner tube to seal the petcock fitting and an old bit of pipe to join the crossover outlets together and a short bit of pipe with a self tapping screw in the end to block the vent/overflow
then it is time to build some upper body muscle with 30 minutes of sloshing then a wash out with each of the different stages of chemicals
yes it is a pest but some stuff you just have to do to be who you are
Brian