Any chance a saginaw would ever get hooked to a L35 MW in 68?
Not from the factory. The only manual transmissions available on the 396/325 were the Borg Warner M13 three speed or the Muncie M20 4 speed.
Ed
Is the Borg Warner cast iron?
Yes it was. Kind of rare too, if you have one. Most folks that wanted a big block (and a manual transmission), went with the Muncie 4 speed. Only 752 M13's installed in 1968.
Ed