Their were two 283 casting blocks. 3737739 - Chevrolet 57-60 Pass. & Corvette w/8-283 with Fuel Injection. A side note in the manual on this casting block. "NOTE: When installing on 1957 must use two 3748768 head gaskets to prevent water leakage." 3756519 - Chevrolet 57-60 Pass. & Corvette WITHOUT Fuel Injection. Chevrolet 59-60 Chevrolet Trucks. Those were the only two casting numbers for 283 I could find.

Looking for engine cast #'s and other under the hood #'s, bellhousing,etc.