The challenge lies in the bellhousing pattern. The 305 uses a small-block Chevy bellhousing pattern, and the TH400 was used across many GM vehicles with different bellhousing patterns. You'll need a TH400 with the correct small-block Chevy bellhousing or an adapter plate to mate the two.
In short: Possible, but not without some work. You'll need the right parts and potentially a mechanic's expertise.
