I seem to recall hearing somewhere that a 235 head would fit a 261, the only difference being the small coolant circulation holes between the chambers needed to be drilled on the 235 head to match up with the holes between the cylinders in the 261 block. I can't verify - maybe some of the other Bolters can. Good luck!

1941 Chevy 1 1/2 Ton Master
"Always do right. It will gratify some folks and amaze the rest." Mark Twain