Engine Block Heater

I have a 98 Z71 and just had a block heater installed with a GM heater and cord.
It doesn't seem to heat up very much overnite.
When I start it up after it's been plugged in overnite, it takes about a minute for the heater to get warm and it's barely warm at that.

I used to have a 4.3 S-10 with a blockheater and it was really warm right after starting up.

Is this normal?

Is the heater element bad?

The local dealership installed the heater in the drivers side freezeplug towards the rear of the engine.

Thanks

mine came stock with one and it normally heats the coolant to about 90*F which is just above the bottom of the gauge reading. It is only desigined to keep the block warm, not at operating temp.

Thanks for the info!!