My way of doing mine, which was on an 8050. I got a few gallons of high end long life antifreeze and 5 gallons of distilled water.
On the right side of my engine was a 1" npt plug with a recess 1/2" square drive.
I pulled the plug out and measured how much depth I had and ordered a 1"NPT x 3" 400 watt heater and installed it (between#2 and #3 cylinders) I pulled the lower radiator hose and blew thru with my airline before I installed the heater, flushed it out twice with plain water, then added enough anti-freeze to be a 55-60% anti freeze mixture and topped it off with more distilled water, I had to pull the manifold heater sensor out to bleed all the air out. According to my manual the anti-freeze is to be changed yearly with the factory fill.
I have been satisfied with the block heater, I do need to do one more thing before next winter, when the heater is used the manifold heater will not stay on long enough to warm the intake air, i have to cycle the switch numerous times to get some heat in the intake, below zero (F) it doesnt like to start without manifold heat, I need to see how the cycle works if I disconnect the sensor or if Im going to have to get another sensor and mount it where it reads air temp and a switch t go between air and water temps. As far as cost goes for electricity at 16 cents per KW every hour is .4 of a KW which is 6.4 cents per hour.
Enjoy
Lou