difference between alpha one gen 1 and mc1 style prop

[Chevyls6]

So im getting ready to slap a new prop on my alpha one drive and i see in the parts breakdown that there are 2 different thrust hubs depending on what generation of prop you use. How can you tell which one you need?

 

[Bt Doctur]

most newer style use the thinner thrust hub. some old props like Michigan use the thick one..
Should you guess wrong, when you tighten the nut you will jam the prop against the case, you needed the thick thrust hub .If you tighten the nut and the prop is not seated all the way ,you need the thinner one

 

[Chevyls6]

most newer style use the thinner thrust hub. some old props like Michigan use the thick one..
Should you guess wrong, when you tighten the nut you will jam the prop against the case, you needed the thick thrust hub .If you tighten the nut and the prop is not seated all the way ,you need the thinner one

Thank you that clears things up. When i torque it down the prop turns freely by hand just wanted to make sure.