300 searay

I am repowering my 300 weekender that has twin 5.7 (260 hp.each) and 1.52:1 direct velvet drives/ with 17x16 props The new setup that I have already purchased is twin 6.2 383 Mag Strokers (340 hp.each) and 1.91:1 direct velvet drives. I need help figuring out what props to purchase for the new...

I picked up a 1986 300 30' Searay this AM from a foreclosure property. NO motors but some other stuff like hatches , low profile windlass(Benson), swim platform etc Willie 631-235-0186 More photos can be seen here http://longislandmarine.us/ZenPhoto/index.php?album=searay-300-1986