Depends.....if the 235 is a 55 or newer you're headed in the right direction. If it's an older low-pressure babbet engine I'm afraid you're taking a giant step backwards.
You need to ID the specific year of the 235....hopefully it will be at least a 54 (insert bearings) or maybe even a 55-62 mill.
A 54 engine would switch in without any issues and the radiator would have clearance from the fan. In a 55-62 install you'd need to use an adaptor plate to adapt an "early" style waterpump to the block and give yourself proper fan clearance.
Before I did anything I'd check out the 261 block and see why it was stuck. By far, the 261 full pressure engine is the preferred upgrade to add a little "zing" to the pickups.....I'd ID both the 261 and 235 for their years of origin, figure out why the 261 is "stuck" and if not feasibly repairable, go back to a full pressure 235. Hope this helps.
Dave
