The truck is a 1980 ford 302 motor. The engine always started as soon as the key was turned. A year ago, when we purchased the truck, I had a local shop rebuild the carburetor after an overnight soak. About a month ago we had the heads rebuilt. Truck came back running great. Engine started as quick as before. The last two weeks it appears that the engine struggles to start (taking about 3-4 seconds to start) when cold and a bit longer when hot. Engine runs great otherwise. Could it be the timing is off? Choke stuck? Any ideas would help.

Thanks

 

I would try setting the choke first.