i had the 1990 ford master cylinder and the 94 nv4500 slave and if you held the clutch in for more than 15 seconds it would start slipping back into gear and the ford master cylinder didn't have enough throw to full disengage my clutch the hd 5600 hydros i got i had to shorten the throw rod 2.875" to get it to work but its as smooth as pie now

 

use the ford master and use the slave from a 96 jeep wrangler 4.0 the bore and stroke are the best match for our setup I have mine n and still have a little air to work out yet it seems to work just fine