Hi4rw1n,
We used to have a MF 135.

I would call that metal cover a "hood," or an engine "cowl."

Do you have photographs taken at 90 degree angles? And dimensions?
Front view, side view, top view? If so you can load the images into MoI, with View Image, and then make 2D profile curves.
Others have posted on the forum about starting with say a rectangular cube, and Trimming or Boolean difference, away parts of the cube,
and then doing Fillets. So it is a subtractive process.

It seems that most photographs are taken with the machine at an angle, but there are a few front view out there.

- Brian