I need a good set of exhaust manifolds for a 371. Anyone have set they want to sell?

 

I believe 57-58 and 59-60 have different manifolds. Do you know what year of 371 heads you have?

 

I believe they are ‘58.

 

There will be a two digit number cast on one exhaust port on the head.
#14 is 1957
#16 is 1958
# 18 or 20 will be '59 or '60.

 

Yes.

 

Here are the photos provided by the shop:

 

What you have there is one 1957 head (#14) and one 1958 head (#16).
I don't know if these heads both had the same size chambers.
I know there was a compression difference between 1957 (9.5 to 1) and 1958 (10 to 1).
To me, it would be important to CC the chambers on both heads to ensure that all eight cylinders have the same compression ratio.