For what it's worth a 37" tire is likely no bigger in diameter than 36". 6" lift will work fine as long the rear of the front fenders have about 2-3" trimmed from them at the bottom, and about an 1" or so angle from the front bottom Put them on and cycle/turn them to full lock, have the sawzall and a cut-off tool handy, cut as much as required, paint exposed steel with something durable. Moving the housing forward 1" should/will help eliminate some metal removal. For a few hundred dollars, cut out flares do a good job too. Plus many states have laws concerning exposed rubber outside the fender.
My brother in law ran 39's on an IFS Burb for years with a 6" lift FWTW. He even pulled a 32' travel trailer all over the country with it.
