All 54-62 crankshafts will interchange in '54-62 blocks. 235s have "tapered mains". This means that the main journals of the crank get larger in diameter from front to back. They were designed that way. The #1 front main is the smallest and the #4 rear main is the largest. Take all parts to a good machine shop, they'll know what to do. And if they don't, they aren't a good shop. These motors are still very common (for an old motor) and a good shop will have seen one in the past couple of years.
The '848' head is the one to use, its got slightly smaller combustion chambers, yielding better compression. Make sure all parts are magnafluxed for cracks. All bearings, gaskets and other parts are readily available for 235s/261s, thru NAPA or online stores.
good luck
chip
