The correct carb for your application should be stamped 70405XY
70= Rochester Carburetor
4= 1970-1975
0= 1970
5= California emissions
X= 0,1 or 2= Chevrolet
Y= transmission application Odd #'s 1,3,5,7,9 for manual trans, even #'s 0,2,4,6,8 for auto trans
Quadrajet Power LLC has some nice photos of a 7040502 that you can compare yours to.
https://quadrajetpower.com/chevrolet...rajet-7040502/
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'51 South Bend Model "9A"
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