That looks like a high-pressure, 1954 and later, 235 block.
http://chevy.oldcarmanualproject.com/shop/1954truck/54ctsm0623.html

Can you post a photo of your head gasket, and a photo of your head gasket sitting in place on top of the block?

If all bolt holes line-up, and you have extra holes in the head gasket, are they located over the the locations for the extra coolant passages on the 261 (link given in a post above)?

By the way, there looks to be serious corrosion-erosion in several places on the mating-surface on the top of your block.

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.