Plymouth Valiant 61 Manual upgrade query

I guess it's possible as you're in a different country, but here, the A230 didn't appear until late 60s or maybe even 1970 as far as I know. Having said that, if it is indeed an A230, then the A833 4 speed will fit where it is, with the proper bellhousing and clutch linkage, of course. I would endeavor to verify the A230, though.
Ahhh seems that's where I'm getting my wires crossed... I'm looking a car stateside, so you should be on the money with what you said first... So that means we both still need to try and find out what manual trans, if any will fit as.an upgrade? ...Another question I had, will a 904 Auto fit without any tunnel mods? That way you could retro fit (potentially) a Lokar type floor shift kit I was thinking