That 'sensor' you're looking at on the lower intake is for the temp light, so you're on the right track. I think there's at least a couple of pipe plugs on the rear of the lower intake, but you'll have to poke your head back there and check. You should be able to stick a sending unit there. Don't worry about the computer throwing a fit, it uses a totally separate sensor from that one. I understand you wanting to put in a gauge instead of relying on a light. I'd want to know if I can do anything
before my head gaskets blow.
If you end up having no extra coolant holes, just take out the idiot light switch in the intake and replace with your gauge sending unit. Simply tie off the wire that was going there, and as long as it doesn't touch ground, you have nothing to worry about. Good luck.
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Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch 
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