I'm switching my C6 for a ZF5 behind a 351W in my '87 F250 . I have the clutch/brake pedal assembly but it looks like there is no room next to the brake power booster for the master cylinder. I haven't bought the tranny yet so I'd also like some suggestions on the best 5 speed, given my 4.10 gears.

 

The master on the Bronco sits ~8 o'clock on the brake booster if that helps.

Five speed options are pretty limited and they'll all require either a hydraulic or cable clutch. For daily driving the ZF is basically a three speed with overdrive - I don't use the granny first around town. I think most all of the 4x4 capable 5 speeds have a granny gear so it's not a plus or minus.