Hi! Can't find my title right now, but I have acquired either a 1973 or 1977 hi-lo that needs a ton of work. But I think it is worth restoring. Was wondering how different the model years in the 1970's were and if someone had some manuals/information I could use? I know it was listed as 21 feet on the title. Any info would be appreciated. I thank you in advance for your help.