It's a diecast produced by First Gear but was available for a time through NAPA stores and latterly were being sold at discount prices... IIRC correctly $35. us... I got a few of them at that time. Cliff combined one of them with a resin kit cement mixer rig. (more). *PIC*
I had asked Cliff about the cement rig because I thought its proportion really fitted better to the Mack than the AMT ones available in kits at the time.
Cliff also did another conversion using a resin sleeper cab by AIM. He's shown it here before.
Raymond Gallant