Helomech has a F1c or a F2m 4v in his fox body- can't remember which. so ask him about dimensions there. the f1 blowers do rotate like the others- you just have to make sure that you reclock the oil slinger gear so that it is in the bottom of the blower case once mounted. F1a and F1c outlets are 3" ID but I suggest 3.5" which I have talked to procharger about and it'll work just fine. I use 3" from blower to IC, and 3.5" from IC to TB.
Im using 3" from Blower to innnercooler and then 3" to TB, Im also using a VMP 3" Meter. I have the Big Red Closed version Blow off right now also.