what's missing off this carb?

[Kevin Cozzo]

hey was thinking about getting a 40 dcnf carb, and one of those repo manifolds mentioned in the fs&w section, and found this, but something looks funny, isn't there a top section missing?
http://www.ebay.com/itm/152653304217?ul_noapp=true

 

[Dr.Jeff]

It's not really "missing" the top-cover, but rather the top-cover has been cut off or trimmed down. This is typically done so a "air horn" (velocity stack of sorts) can be added. Seems to me removing the top portion (altering its design) would effect the function of the carb to some extent. Here is a pic of a whole one:

And here is how the air-horn is added:

 

[Brad Garska]

Actually nothing is missing or modified - just a different version with different top covers.