By 1976 was probably the 351M - Modified Cleveland
There was a 400M derivative if memory serves
1971 351 Cleveland had higher compression
My 1972 Mach 1 had a 351C 2 bbl but lower compression like 8:4-1
Converted it to a 4bbl with an Offenhauser aluminum intake Holley 780 vacuum secpmdaroes
The 351 Cleveland made it into the 1973 Mustangs and Cougars low-compression like my Mach 1
Those were great days - Bob Glidden was killing it in those days in his class
THE 351 Cleveland engine also had 4 bolt mains...
The Windsor engine had only 2 bolt mains—made in Canada.