All small blocks can be told apart at a glance by looking at the crankshaft flange....

A 283 crank flange is fully round (circle shaped)
A 327 crank has a notch out of it...Like from 9 O'clock to 12 O'clock

A 350 has 2 notches out...9 to 12 and from 12 to 3... not exactly but quite like that....you'll see if you compare...

there are exceptions like the 307 and 305 that share other cranks but have a different bore size....