1974? Starcraft SS 18 Prop specs

[opieone28]

Good evening. I recently inherited my dad's 1974 (I think) SS. I sent the prop in to a local marina and due to covid lock downs have not been able to pick it up until 9 months later. Unfortunately the marina can't find it or doesn't have it. The owner wants to know what size and pitch. I have no idea. My dad had some notes that say 14 1/2 - 14 3/4 x 21. That doesn't seem right to me but I don't know. Inline 4 cylinder mercruiser.

Can anyone help me?

 

[jbcurt00]

If it's a 1974 Starcraft SS, it'll have a HIN plate @top right of transom viewed from behind.

Don't have a mercruiser so can't help w prop

 

[jimmbo]

You didn't get any paperwork when you dropped the Prop off?

 

[Watermann]

It would be a 120 HP MC drive with a 1.98 gear ratio.
I would recommend a 14 1/2" diameter x 19 pitch spline tooth count 20 - 24. Due to the age and wear on the motor trying to spin a 21p prop even in a light 18' Al boat can cause lugging issues not being able to reach max RPM at WOT.

Props are spendy so you want to get it right because once installed it's yours forever. I prefer the 3 blade Quicksilver Black Diamond Al with the hub kit for my Mercruiser stern drive Chief.