Relax. This is an easy repair if you take your time with it. You will need to go to any auto parts store and buy a helicoil kit. The size you need will be 6mmX1.0 The kit will have the correct drill bit, tap and installation tool as well as several helicoils. While you are at it you should helicoil all 4 cylinder studs. While you are ther at least pick up the 5 mm allenwrech you will need to remove the left hand blower houseng. And pick up a couple of spare heli coil insets( this wont be the last time you need them in your life) The kit will usually cost between 20 and 30 dollars but all you have to do is use it twice for someone else and they have bought it for you. Make sure you take precautions against letting any of the metal shavings fall into the crankcase by taping off the opening or stuffing a rag in it. It sounds as though the cylinder head nuts are frozen to the cylinder stud so you will want to either soak or heat the nut so that it can come off of the stud. After you have done the helicoiling, screw the studs int the block then slide the cylinder on making sure to proerly align and compress the piston rings. It will be a lot easier that way because the cylinder wont be floping around It will ride on the studs. Also with the blower housing off you will have much better acess to both sides of the cylinder. When you torque the cylinder head down tight it in several stages and in an X patern. If you have reused the original head gasket torque them down to about 12 ft lbs. and 8 to 10 ft lbs if you used a new gasket.
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