Relatively speaking the Idaho title process doesn't sound overly expensive or horrible.

https://itd.idaho.gov/dmv/vehicleservices/documents/conditional_titles.pdf


That being said, you can always expect to run into an employee who is not familiar with the process and that gathering the required paperwork/inspections will take longer than expected.

The only thing that would concern me about the 37 is if you are correct about it having to have an engine to get a title for it. I personally would not put any additional labor or parts into it until I had a clear title in my name. Of course I would not be above throwing any old junk engine in the back of it and telling them it will be going in the truck when I build it if I could get away with it