I had a 235 with crack in same place, didn't leak much at all and just kept on driving. Some block sealer might help.

Otherwise a later model 235 or 261 are well worth considering for a swap, very simple.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-