Just for 1 trip is this worth it

[1974ChevyC10]

ok in the next 2-3 weeks im going to drive my truck to las vegas.it currently has a 600 cfm carter afb.i also have an unknown cfm qjet at my house thats been rebuilt.here is my engine setup.
edelbrock performer intake.
260 duration/440 lift cam-i may not be totally on the money with the correctness of that one but its close to that.
stock hei
1 5/8'' hedman headers.
2 1/2 dual exhausts.
carter afb
double roller timing chain.
what im wondering is would be of benefit to me to swap over the carb just this once since it gets lousy gas mileage with the afb.i dont expect it to get stellar mileage i just want it to get better than the like 9 mpg's it gets.