Old film development

I have found an old roll of 616 film in my Grandfathers folding Kodak camera that has been exposed. It's on an Ansco spool, but no clues to the film manufacturer. All I can see is the brownish backing paper that says "exposed".

Any guesses as to a development time? I was hesitant to do a clip test since I don't want to cut an image in half. I have some benzatriazol to use as a base fog inhibitor, so any suggestions as to amount to use and developer/time combination would be appreciated.

Woohhh!!
Took a little bit of "searching here --

I developed a roll of Ansco "Plenachrome" - found in an antique shop ... in Rodinal 1:25 for 7 minutes @ 20 degrees C... the result of a clip test.

Check out my post - and the others on this page:

Go to the top of this page and enter [ search ].
From there, enter [ Plenachrome ] and [ search for terms or use query as entered ]. Enter [ display results as topics ]. You should arrive at "B&W: Film, Paper, and Chemistry.
Then select [ Your thoughts on antique film development ].

*Should get you there. Note the comments on benzotriazole.

I would try split development and clip a few inches off and develop it as a test first - see what the base fog is - It will be high. I'll bet there are special brews for this but I don't know them. The advantage of split development is that it will prevent runaway development of overexposed areas. My tanks won't go to 616 - It is 2 1/2" it think.