If that vent hose in your pic is cut off like that, I bet you smell gas! Your truck looks like an evap tank. Do you have a metal line running up the b pillar on the pass side? My old memory remembers that '69 307 Calif. emission 1/2 tons got air pump & eec tank & carbon canister etc. Some Calif. 350's had evap tank, some not. My '70 has an evap tank, original to truck, so some(california) got them before 71-72. If your going to keep all your emission stuff up and running, I'd replace all the hoses in the cab, proper gas cap, make sure vac line at carb is hooked up for the carbon canister. Before replacing your tank due to a leak behind driver (top corner vent hose?) make sure that vent line is not split. Hope you get that smelly truck fixed.
