305 wont start below 40 degrees

My 305 wont start when the temp outside is below 40 degrees.
i have to leave a drop light sitting on the manifold all night to keep the carb warm, and i have to spray it with starting fluid every morning.

i had a Holley street avenger 650 on it. it ran rich and backfired whenever it was cold. it also had a bad dead spot off idle. i hated it.
so i went to a Eldebrock 600 mech secondaries and manual choke.
it runs great, but it still wont start if its too cold. Please help!

is the battery in good shape? if its an old one then that may be your prob.

also is the engine in good shape? and tune? old coil things like that

You might check the choke and linkage, especially cold. I recommend cold, as it will allow you to actually check the operation, looking for sticking linkages, poor adjustments etc... When the engine is cold, the choke should completely close and raise the idle to about 2000 rpm. The rpm reading is relative to the operating conditions, but the choke should close completely. When the engine starts, the choke should open slightly, allowing the cold engine to breathe. A cold flooded engine is a bear to relight. Ray

Thanks guys, i found the problem though. It turned out that i was getting little to no spark when the engine was cold. i pulled the distributor to find it was worn, dirty and useless. i bought a reman for 100 bucks, put it in and it fired right up! Now my truck will crank even below 25 degrees!