Nope --- figure a year or more... because there's no way you'll get out to the garage 15 hours a week every week... and it's easier to tear stuff apart than it is to put it together... and sometimes life gets in the way... and sometimes you just don't get much done... and some weeks you get a whole bunch done. But the reality is that there is always WAY more work than you expect - and sometimes you are waiting on parts... and sometimes you can't find the parts... and sometimes your buddies come over to help but end up just drinking your beer.
You should take on the project -
just don't set an unrealistic deadline. Doesn't sound like you've been working on these for the last 20 years -- so there's the practicality of knowledge - skills - tools.... etc. Treat it as a hobby - enjoy the "process" -- the hunting and the gathering -- the friends you're going to make (#1) and the pride you'll gain when you complete each step of the process.