Cast Iron nose Starter Bolts 1971 K10 350 4spd

[Mr Chevy]

Hello everyone, first off: Go Seahawks!!!
Ok now with that out of the way. I have a 1971 Chevy K10
Previous owner put the automatic trans alum nose starter on the truck and it isnt starting correctly. I purchased the proper cast iron nose cone which i was told Im suppose to have for a standard trans but the alum bolts up to the block the cast iron nose bolts horizontally to the bell housing. I need to know what size bolts to purchase to be apply to install my new correct starter.
Thanks in advance for your help.