Yep its true though. Read the cam card on Cranes web site. 6000 valve float occurs. I am shifting the truck the same as you and I don't have any problems but I am not willing to risk my valves on that Crane cam.

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

 

If you are running strong enough springs, you won't get float at only 6000. I have pushed my rev limiter to 6400 and shift in the 6200+ range. On the dyno, my curve is flat past 6200, so I don't think I have any float.

Everything on the 2001+ 6.0 engines will bolt right up in place of the existing 5.3. If you leave a mild cam in, you could easily get away with stock tuning.

 

Thanks BIG TEX for the conversion infor. Sounds like a fairly basic swap. I can see a 6.0l, little head work, medium size cam with LS1 edit for tuning and a 2800 converter, sucker should go 13s easy and still be reliable as a stocker. Damn, now all I need is the $5k to do it. LOL