[Aaron65]

I have 6 cars, all with mild engines. I live in Michigan, so I drive my cars whenever the roads are dry and salt free, usually some time in March to as late as early December. I start them from as cold as 25* F.

All have heat operated or electric chokes, but only my slant six Dart has a fully operational heat riser. The rest have missing or blocked heat risers, and my 289 Mustang has a blocked crossover (which was a mistake...it runs ragged when cold).

The Dart starts the best cold; I can usually take off on a cold day almost immediately, even though it misses and spits a bit for a short time. There is almost no hesitation. My Firebird is almost as good; it is only missing a heat riser but still has manifold heat.

My '53 Buick has a wired shut heat riser (it heat soaks otherwise). It requires a lot of careful driving so it doesn't stall when cold, as do my Skylark and Mustang. They all have tip-in sags until they are sufficiently warm. The Corvair will start and run OK cold, but it has a fairly large tip-in sag until it gets hot. I have another set of carbs to try on it; I think there's a quirk in its current carbs, as it has always had a slight tip-in sag at higher speeds.

Wow, that was a long winded answer to a simple question!