NOS Mopar Chryco 1710913. Found on the net listed to fit:
1956 1957 Chevrolet V8
1957 Corvette with fuel injection
1957 Chevrolet high performance engines
My Mopar book says says 57 Pontiac model 20 and 22 V8.
4 here at time of listing, two box types, add a note if you want a specific box.