Glyn -
Your best bet is call the tech service folks in Jackson Center, OH. (Check
web site for number)
Leave a message as to your question and they will call you back with the
correct answer.
I can't remember what the dimension was from the front end cap edge but
they will tell you.
I think it was 60 some inches on my 64 Tradewind, but may not be the same
for yours.
Blair
Hangin' in Key West