Mustang intake plenum on ford crown victoria?

I bought a professional products intake plenum to install but the mustangs only have 3 ports on the plenum where crown vics have 4 which its missing the pvc. People are saying just T it off but I'm not 100% sure which vacuum source I should T off the pvc to. Its confusing because I see mustangs have lines going to different places on there plenums then the crown victorias do. If anyone could give me any info or send me links with close up pictures or anything it would be appreicated thanks