Those rubber mounts do fail from time to time. Generally because of a lot of torque (squealing the tires). I know this because I put a 350 Chevy in an AMC Javelin AMX and eventually had to put a chain on the one side (motor torques in one direction) so under hard duress the chain took over instead of ripping the motor mount out! It could also have been abused when taking the old engine out and putting in another so don't get to hard on son yet. A motor mount isn't reason to pull the whole engine and spend the money going through it. Also if son isn't interested, chances are it won't get done or done correctly and one bearing in backwards will cause disaster. The rubber dampens the vibrations, I would look on ebay or for a junkyard and buy a used one. If you have a junkyard that allows you to take off parts, that is the place to start, practice on their car so when you get home you know how to do the procedure without denting the fenders of your auto!!
God and family, the rest is icing on the cake.
I'm so far behind, I think I'm in first place.
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