The 4 cylinder engine was a very well cast piece, ditto for the chain drives.
As seems to be standard across the kit range, measuring accuracy is certainly demanded.
As i foundout (and was only saved by some scrap plywood) when the instructions say 115mm or suchlike between the cut in on
the wing strut top and bottom for example, that is exactly what it means.
Trust me, +/- 1mm difference matters on this one.