250CI I6 Problem

[PanelDeland]

http://67-72chevytrucks.com/vboard/s...d.php?t=148346

That link is the best HEI specific to a 250 6 there is.

You may need to rebuild the carb and replace the filter in the carb itself.You also should know the intake and exhuast manifolds are connected under the carb.The heat from the exhaust warms the intake.The 6 has an open design intake and the fuel can condense in the intake.This heat exchanger helps warm the mani to prevent(somewhat) the condensation of fuel.There is also a heat riser in the exhaust system,usually between the exhaust manifold and the exhaust pipe.It is a spring loaded damper which helps keep heat in the exhaust mani at start-up.It has a bi-metal spring which expands/contracts with temp change.As the engine warms the spring this heat riser opens allowing exhaust to flow more freely.Make sure the heat riser will open/close by hand(you are less likely to get burned if you check this while the engine is cold.Then warm the engine and make sure it is actually changing position as it warms.
After my HEI swap I haven't had this problem but then I did it in early spring so the temps did not affect the mani temp as much.