Triple John's option for cylinder removal...

1) Partially tap all four stud holes with a 5/8" tap. Do not tap all the way! just 1/2"-3/4" to get the bolt started. You will need all the thread strength you can get. The bolts will pull out VERY easily if you tap all the way down.
2) Soak cylinder with WD40 or PB Blaster, heat cylinder a little while, then turn ALL four bolts 1/4 turn at a time. Make sure you tap on cylinder lightly to help things along. Once you get the cylinder to lift 1/4" or make sure you tap cylinder back down onto the case, and start over. This will take a while, but it will work.
3) Once you have the cylinder freely moving on the studs now is the time to use the piston removal tool. Drop a small piece of 3" round  3/8" plywood into the bore. This will keep the center of the tool from moving around in the bore, and also protect the piston from being damaged.
4) Thread the two slotted bolts into the cylinder as far as you can, and slide the puller into the bolts. Make sure that both bolts are at the same height, and the puller is centered in the cylinder.
5) Start turning the puller bolt clockwise until you make contact with the piston. Once you make contact give it a half  to one turn, and apply penetrant, and heat. Let it sit for 5-10 minutes give it another turn apply penetrant, and heat.....Be Patient it will break loose!