Dickson,
There is no need to swap to an open drive-line just because you use a newer engine. And, there is no need to change to 12v just because the newer 235 came in a 12v truck.
I have a 1960 261 engine in my 6v 1954 1/2 ton truck with original clutch housing, clutch assembly, and enclosed driveshaft.
The 261 engine is the same physical size, with same mounting capabilities as a newer 235.
The is absolutely no "necessity" to change to an open drive line.
