make that +2
if you are running 35+ tires you might want to think about re-gearing at this time, since you are already in there.
ahh... the eternal debate about whether to regear...ever read that story "if you give a mouse a cookie?"...about how if you give a mouse a cookie he'll want a glass of milk, then a story and blah blah blah...gears have always been that way for me. "I'll just stick a detroit in the rear...well since I'll be in there I'll do it right with new bearings and seals, might as well regear...of course then that means the front too...and bearing kit for the front"... what was a relatively cheap (only by comparrison) upgrade, has now turned well into at least a 1500 dollar ordeal, plus a couple fluid changes for breakin, not counting whatever is to be done about the speedo...the things we do for performance. It's just money right?
Just my two cents, been down that road a lot. Good luck.
Also too, I have heard, and it's only been heresay, no personal experiance, but I've heard the truetracs don't hold up as well to bigger power, and bigger tires as well. I do know they don't function with a wheel off the ground. I got a truetrac in a 69 mustang with an 8.8, and it works flawlessly, but that's almost always on dry pavement, and with both wheels on the ground...both rear wheels that is. Food for thought depending on how you intend to use it. I'd vote straight detroit locker...had them in a few different trucks, the newer ones are much quieter than they used to be...and smoother. make that three cents.