[FORDman77f1]

i have a 1977 ford f-150 custom 4x4 that i am building.it has a 2 barrel 351 cleveland. I was told the engine came out of a 1973 mercury cougar. i am trying to find some type of identification numbers on it. i have read that originally there was a tag placed near the coil. in my case, the tag has been removed. where else on this engine can i find some id numbers??? any information wil help!