changing from alum to SS
 

nova 250 aprox 5500 pounds twin 302's 188hp each alphas, running 47@45~4600 rpm with chewed up 13 3/4 x 21's going to Stainless..do I need to find a direct replacement or is trhere anything I want to change??

i wouldnt think you would change anything , just a basic 14x21 non cupped pair of SS props should suit you fine , maybe even break that illusive 50mph mark

I might have some used SS props that will work great for you.

PM me if you are interested. You can test them first if we determine they are a good fit.