Although it bolts directly in, the rear end geometry of the Mustang is less than perfect in the Cobra. Weld puts out a set of upper control arms with mounting brackets that go on the rear end. It raises the mounting point up by about 1" and has adjustable links so the pinion angle can be fine-tuned correcting the wheel hop issue inherent with these cars.
As for the engine:
1990 5.0
Rebuilt stock bottom end with the exception of a windage tray.
Stock heads .010 off the deck bronze valve guides and valve job
1.7 roller rockers
155lph fuel pump
24 lb fuel injectors
73mm mass air
65mm throttle body
Roller timing chain
Accel 300 ignition
9mm wires
1 5/8 unequal length shorty headers
Valeo clutch
5.0 shifter
3.55s in the rear
K&N air filter
electric fan
See Ya at the track