There was a change to the bell housing (clutch housing) at about this time. There also was a change to the 4 speed transmission. I don't know if the 4 speed from the 46 will fit the bell housing from the 235. If you want to stay with the original 6 volt starter then put the 6 volt flywheel on the 235. If the bell housing transmission bolt pattern is different then use the bell housing from the 216. It might be easier to keep the old bell housing for many reasons. The trans will fit. The clutch linkage will fit. There is an advise in the manual about moving the Master Cylinder..so that won't be an issue. If you want the 12 volt starter then put the 12 volt flywheel on and you are good to go. Looks to me that the bell housing and the 4 speed transmission changed 46 to 47. That is the reason for the concern about the bell housing. It won't matter to the starter They will fit. It wont matter to the flywheel, they will fit. It might matter to the clutch, throw out bearing, linkage and possibly the release arm. And it will matter if the bolt pattern for the transmission is different.
If it were me I would use the bell housing from the 216, keep the 4 speed trans and keep the 6 volt starter and flywheel. The 6 volt starter will work with a 12 volt system so it is not a big deal. That would keep any other issues to a minimum. Just my 2 cents worth. I may be all wrong so keep in mind these are only suggestions.

Steve H