dresmnkaos
i think your talking about a sensor that you needs to be drilled and tapped. if so then you need to tap it for a 3/8" NPT since all the sensors are tapped that size.
no need use the sensors for a 1990 5.0 mustang they all fit
I believe this is the tread you talked about earlier?
if not then this thread has all the info you'll need.
http://forums.stangnet.com/showthread.php?t=551505
that should be all you need if you are bolting a upper tubular gt40 to a matching either cobra or gt lower from everything i've read, but i'm sure get all the info you'll need real soon
that thread sucks most of the images are missing. I will make a new one if an admin will make it a stickey