The problem with a heat lamp is that your snake needs heat all day & night, but they need a reasonable photoperiod too (ie. they need darkness at night). So you could use either a CHE (ceramic heat emitter) which puts out heat only but no light, or maybe a black incandescent bulb (there is disagreement about whether or not the low-level purplish light actually disturbs a snake at all), & in any event, think about SAFETY.
Heat lamps should be fixed so they cannot be knocked over (by family or other pets), because the last thing you need is a house fire. All heat sources should also be controlled by either a thermostat or at the very least, a rheostat (aka "lamp dimmer"), & checked frequently to make sure that the snake's home is maintaining the proper temperature range- not too cool & not too hot. The "warm side" as it is now is way too low- you want a BP's home temps to range from 88* warmest to about 78* coolest. (roughly)