Slant block to 904 bell-housing bolt specification

3/8-16 and 7/16-14 arent both NC and NF thread, each one you list is NC ("National Coarse") NF is more threads than that per inch. 3/8 NF would be 3/8-24 and 7/16 NF would be 7/16-20.

Yep, bang on. You're correct as I was fast typing before getting on with today's work. Sorry for my error.:thumbsup: