From another forum:
C7ME-A Blocks can be a car 428 or 390/360. Easy way to tell is to pull out a plug (#1 would be the easiest to do). Use a long rod and measure the stroke. If it is close to 4" then you got a 410 or a 428. If it is 3 3/4" then its a 390. If it is 3 1/2"...... Well it could be a 360