Raceron1120 is correct about the ''b'' post being SLANTED on '41 to '48 Chevys and other GM's.
Also, the back of the hood on '40's Chevys runs allmost straight up and down, where it lines up
with the side cowl, and even though the picture isn't very clear, you can see that the side
of the cowl points forward to a 'v' shape like'41-'48 Fords and Mercs.
.