Yeah, a grand (or less) sounds decent for an L18. The G-van L18 has the correct accessory brackets for ease of swapping into older trucks too (providing you want to run A/C). L18’s were not known to have piston slap like the early Gen III small block. 120K isn’t many miles in the grand scheme of things. I would be curious about the maintenance history on this engine. Both my 8.1Ls rattle but the noise is the trans release bearing more than anything, which would not be the case with a G-van with a 4L80E.