Help me figure out what motor this is

find the casting code on the underside of i believe the driver side near the motor mount? c designates 60's d designates 70's e designates 80's and f designates 90's. to determine the year of the block look at the first two digits on that code the decade designator ie cdef and the next digit to indicate wheater it was say a 71 or 78 or 88 for example d1 d8 e8 the lifter valley should also say 351 if its a 351 i beleive mine do