1969 Barracuda Carb Suggestion Needed

If it's a carb option you want, I'd go with a 750 double pumper Holley means it's a 4 speed. Won't be the "best" mpg options, but it won't kill it either if you stay out of it.
However, if it's as dead as you say, it could be numerous things. I'd personally start with the simple tune up of plugs (plugs can tell ya a lot), plug wires, cap and rotor. If it's points, replace them too. Then I'd set the timing by moving the distributor. See what the best you can get it from this. IF the car continues to struggles to cross the street, that would be another conversation with another list of things to check, but I'd first eliminate the simple things.