The drivers side is easy money just swap them out. The pasenger side you will have to take the bolt out of the passenger side motor mount and jack up the motor a little bit. You will also have to remove all the hoses that go to the smog pump.
When you lower the motor back down just keep wiggling the header to make sure that nothing is in a bind.
The job will take an hour or two.
GOOD LUCK
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88 mustang gt convertible bored to 306 BBk equal length headers mac cold air fender kit 3.73 FMS gears cowl hood nitto drag radials ford racing clutch flow masters h-pipe 160* thermostat 16 degrees of timing electric fan off 94' t-bird jacobs electronics cap and wires. Edelbrock 1 1/2 inch drop springs.