Difficulty of modeling certain items.

I am going to start practicing modeling, mainly because of the lack of engine parts out there and specific sized shapes and objects, i would like to know though, how long would it take to get a steady realization on modeling a complete engine block, cylinder heads, intake manifolds (1-4 per engine), oil pans carb’s, ect. these are for v8’s so don’t get your hopes up you 4 or 6 cyl ricers. also i want to model a dash for a dodge coronet (68 -70)

also would it be easier to model a entire engine or a block with separate parts, which would be awesome.

I am looking for
1.How long it will take to complete 1 or 2 said items
2.Base amount of time till i can get a firm grasp on modeling
3.Tips
4.Suggestions to help me.

Thank you for your time and co-operation.

If it’s just for show and you can’t actually see any of the parts, make it one mesh. If you want all the parts separate, make them so. And to answer your questions:

  1. Depends entirely on your skills and the level of detail. From hours to days.
  2. Couple weeks with few hours of modeling each day, possibly a month or more
  3. Yes.
  4. Start by picking a 3D program. There are a few (hundred) threads about modeling programs around here.