The International Cessna 170 Association

okflyer wrote:My old headliner showed up at work today, rescued from the upholsterers garbage can. I had that one custom made and copied directly from the original. The zipper is 50". Thanks to everyone that replied.

So it would seem that given Shawn measured his original '48 headliner zipper at 49" and yours seems to be 50". And given how easy it would be to measure each at slightly different places. We can only say the zippers were 49.5" plus or minus .5". But it is highly likely they are 3-4" longer than 46", which seems like it might be the popular zipper used today.