I got the block out of the tank and pressure washed the rest of the paint and white gunk off. I added 1,000 watt emersion heater for about 8 hours, the solution got to about 130F. Did lots of stirring and it seems it worked very well with the heat.
I have not painted the inside yet. I have been scraping stuck on sand and grinding with an oval shaped carbide bit. I'm going to give it a good round with a sand blaster inside then I will paint it.
For now, I got some paint on the outside. I wanted a mellow color, even maybe grey. I found some Detroit diesel green in high temp paint and it has that old industrial generator look.