Slant 6 offi 4 barrel intake

I can't find any info on this mani I just bought
Looks small for my 225 but was "supposedly" on a 73 Duster
Also not sure on what adapter I will need
Mahalo for any info, C
Wanted to put in my 68 Valiant
Maybe turbo ?
Correct manifold, but it is missing the carb adapter.
PS: I would not consider turbo, with that much milled off the deck and head. Your CR is likely too high. Not that it couldn't be done, but will take a lot of work, with control systems.