Free software from google.
"Sketchup"
Compadre "white bear" and I used it to design an assembly line for manufacturing plant in.... 2009? lol.
Impressive...
I tried Sketchup once, was used to all my Solidworks hotkeys, got frustrated and quit...
Realistically, if you're doing this 50 hrs a week, how many cars do you think you will be able to do a year.
(Basing everything off of the work that it took to get the Roadrunner complete)
3-4 ?