i have found that about 95% of the time on fords after rebuilding the motor that you need to replace the radiator and that will solve your problem.
Please help me!!!!!
I would start with checking your thermostat and thermostat housing. See if its regulating. If it is not replace the thermostat.
Ford Mustang seats can be replaced by taking out all the screws, removing the seat, and placing in a new one.
Ford Mustang Mach 1 1969
On the engine end of the upper radiator hose
spring down
follow the top radiator hose to where it connects to the engine the top radiator hose connects to the thermostat housing , the thermostat is inside the thermostat housing
Follow the top radiator hose from the radiator to where it clamps at the engine. The hose is clamped to the thermostat housing, the thermostat is under the housing.
From the radiator top hose follow back to where it enters the block. remove the hose and the thermostat housing and the thermostat is inside.
your thermostat is inline with your radiator.. its in a junction coming off the bottom radiator three hoses plug into it.
its an forgine peice of junk
the manufacture reccomends it be replaced in 90,000 miles