Have you been tracking your gas mileage since you did the rebuild?
Also, I've been reading that there is a 38/38 and a 38/40. Is the 38/38 the 2 barrel carb for F engines while the 38/40 is the 2 barrel carb for 2F engines? Do you happen to know the venturi size difference between the two? I think on a 38/40 the venturis are 31/35. And from Ed Cook's writeup I think the 38/38 has 28/31 venturis. Do those numbers flange up? I think I'm going to tackle my carb at some point and figure out what I have. I know it's a '78 Federal spec, just don't know how it's jetted and if everything is working properly. How is your secondary actuated? Is it linkage actuated?