Welcome Zig, We need a little more info on your Chief? What size motor is it, inboard/outboard or outboard? My Mercruiser 120 on an 18 Holiday runs a 15 3/10ths X 19 pitch prop.
:welcome: Zigg
Like Dozer said, we need more info and of course some pics of your Chief are in order as well, sorta as a down payment for our help.
Also are you starting a resto thread on your Chief? If so just rename this thread. I would think that needing a prop would be one of the last things a guy would need to finish with. If you have a 120 MC let me know, I have a few props laying around here stuck on some outdrives that can be had.
All anyone can say about that is to run her with that prop and see how she does. Too low of RPMs and your pitch is too high, too low is just the opposite.
