I have the same housing installed and it was also leaking at the beginning. 6-7 turns of Teflon tape fixed the issue. Later I installed the T-sensor connected to the dashboard, 6-7 turns of Teflon it it is good.
Keep in mind the direction you wrap the Teflon tape around. I know it is a low brainer, but sometimes I do it wrong at the beginning.
1966 Convertible (Plant: San Jose, CA)
289 2V, PS, AC