Gonna drop this into a 64 Chevy II Nova sedan. The seller didn't know anything more than it is a 250. Any info you guys can decipher would be greatly appreciated

 

F0206A second picture. Serial numbers are stamped in not casting numbers. Not sure what date law went into affect. 1950? But adding serial number was to reduce auto theft by make engines traceable to original car. But manufacturers also used number to give dealer and repair shops a way to know exactly what engine package it is. But as far as swap should work. With some minor modifications. Same block different crankshaft larger bore. And other minor internal differences. Also think it been a long time since I worked on those motors. But you will have to use newer model carb. Unless you manufacturer an adapter for older carb.
good luck
Old school tuner.

 

Thanks man!

 

Yeah, on the 250, its stamped on the block, above the fuel pump.