Thanks. Your front axle is fine for 35's but its ball joints are definitely not up to 37's and they can't be replaced with anything else that is up to 37's either. They are the same ball-joints I have in my front Dana 44 which is why I stick with 35's. For 35's and your 4.0/5-speed I'd go 4.88 or maybe 5.13.
Disk brakes from your Dana 35 will bolt right up to your Dana 44, you'll just need to shorten the hard lines on both sides a couple inches. Rent/borrow a double-flare tool from your local auto parts store than practice on the short lengths you cut off the hard lines. One or two practice tries is all it takes to make a good double-flares.