I recently acquired this kit, and a wood pilot kit, and have decided not to use it. It was produced about 20 years ago by FH&PB Supply [Flint Hills & Permian Basin, I discovered, after googling it.]
It consists of a cab kit, bunker/tank and a metal truck with wheels. The kit includes parts to exrtend the frame backwards.
I also include a wood pilot kit from the same source. The photo above shows (I think) the long pilot - mine is the ‘short’ version. Here’s the two kits and instructions.
Priced at the same as when they were made (no inflation!): $95 +shipping, with no charge for the pilot kit. This fits a USPS Priority smal lbox so shipping will be $8.30 in the lower 48.