Chevs of The 40's has a filter that will fit. It is an AC #P203. They say it will fit '39 - '54 Chev vehicles. So I guess it wasn't 'the standard' cartridge I needed. Thanks for your input.
Rusty,
That is the correct AC Delco Part Number for that filter. (At least, the one that fits in my truck. YMMV.)
For future reference, you can also pick up a Fram C3P. My FLAPS has them, and I saw one in Advance Auto (my backup FLAPS) the last time I was in there looking for fuel filters.
Edit:
Here are some of the common FLAPS brands and part numbers for that filter cartridge:
AC Delco
P203
P204
Carquest
85010
85026
NAPA
1010
1026
Purolator
P70AC
L20701
Quaker State
QSC3
L20701
Shell
L20701
Valvoline
LC3
Warner
P3
WIX
51010
51026
For the rest of the cross referenced numbers, visit Fram's Website and look in the product catalog. Search for C3P.
Interestingly enough... If your FLAPS doesn't have it, try your local tractor or farm equipment dealership. It seems that everyone and their brother used that cartridge at one point or another.