On the Chevy one, if the alt was moved up to the 12 o'clock position, you could really move the driver's blower idler in. Not to mention it would give the belt more wrap around the water pump. I see a big problem with that long stretch of belt between the two blowers slapping around, also.
With the Mopar, maybe mount the alternator down low at the crank centerline and work out the blower idlers from there?