i have a 78 f250 4x4 and the bottom of the carb leaks not bad but it still leaks. i wanna know what is the most common leak and how i could fix it. put a new gasket in it or new bolts

 

OEM carb?

It has an vacuum/intake leak at the carb base?... Correct?... Or a fuel leak down low? Power valve at the bottom of the float bowl can weep/leak (usaully will make for a flood/hard start) as well as the accelerator pump with age.. Carb S/B on 5/16 studs, and shouldn't need to be replaced.. If it's the base gasket, make sure the replacement has the plastic collars at the mounting studs to protect from over torque/bending.. As well as check for carb flange flatness during a gasket replacement.. EGR plate gasket would be replaced as well....