78 ford floods out at highway speed

[huntboy3181]

My dad has a 78 ford that we use on the farm once in a while. It runs fine until you get on the highway. Once you get it into 3rd gear (it's an auto tranny) it sounds like it's flooding out. I'm thinking it's a vacuum leak, but i'm not sure. what do you guys think?

[hotrodstude]

is this a truck or car?? what engine ? carb or throttle body? regular carb. or vv carb? when was the last time it had a tune up?is all the emmision equipment in tack? need more info.

[huntboy3181]

1/2 ton truck with 2 barrel carb, was tuned last summer

[huntboy3181]

351 big block, as far as I know the emission is in tack, but i don't know that they really had anything back then anyway

[Dave Severson]

Could be the float in the carb is stuck, saturated, or just set too high... Take a look at the plugs, see if they're dark indicating a rich condition.