You are going to need an engine that side mounts at the front end of the block. There are two vertical mtg holes beneath the generator bracket on the left side, and two matching holes on the right side just in front of the fuel pump. I know 55-57 235 car engines have the correct mounting holes, I have not seen an earlier 235 that has them and am unsure about 58 and later car engines. 2nd series 55-59 pickup 235's will also have the correct front mount holes. I have a 60 car engine that has the bosses cast into the block but they are not drilled. I've not seen the mtg. holes on a 261 either. In the my 58 Chevy Truck reproduction shop manual it has very clear pictures of the right side mounting points on page 8-10, and a clear picture of the left mount on page 8-11. I have installed a 55 car engine into a 57 PU, and a 56 car engine into a 59 PU. You will need a truck bellhousing, clutchfork, and throttle linkage.
John
