[rotorwrench]

FoMoCo was worried about the bronze and steel metallic plate slippage when they developed the Type F in the late 60s to use in the Borg Warner design transmissions after the whale oil moratorium became reality. Type F will insure more positive lock up of the clutch packs during the shift phase. I would use it if there is any sign of slippage going on but all the old fluid has to be drained out for it to do any good.

My only worry with the late specification Dexron/Mercon fluids is that they are sometimes synthetic based or semi-synthetic and may cause breakdown of old seals. If you replace old fluid with new, keep an eye on it for a while to see if it starts to leak. If a person doesn't know what's in the transmission then it should be completely drained before using any type of fluid you choose.

The old Holley top float bowl type carbs don't like to set around much. As was mentioned, it may be a problem with the accelerator pump. There can be problems with the plunger or there can be blockage in the fluid circuit for it. The check valve may also be sticky.