The conversion shouldnβt be a problem at all, but with tamiya pricing it might be cheaper to buy the Log truck and set of shorter rails? Otherwise buy the plastics to fit the cheapest tractor unit, just make sure you can source them all first π
https://www.amazon.co.uk/Tamiya-300056360-Controllable-Construction-Unpainted/dp/B07NGZLC1V/ref=asc_df_B07NGZLC1V/?tag=googshopuk-21&linkCode=df0&hvadid=399577965760&hvpos=&hvnetw=g&hvrand=15646682278733400996&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007021&hvtargid=pla-669819098339&psc=1&tag=&ref=&adgrpid=85329203255&hvpone=&hvptwo=&hvadid=399577965760&hvpos=&hvnetw=g&hvrand=15646682278733400996&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007021&hvtargid=pla-669819098339
Instructions PDF:
https://www.tamiyausa.com/media/files/56360ml-1136-1cca.pdf